THE  TECHNICAL  PROCEDURES 


FILLING  TEETH. 


BY  G.  V.  BLACK,  M.D.,  D.D.S.,  Sc.D.,  LL.D. 

Professor  of  Operative  Dentistry 

IN 

Northwestern  University  Dental  School, 

AND 

Dean  of  the  Faculty. 


CHICAGO  : 

THE   HENRY  O.  SHEPARD  CO.,  PRINTERS  AND   BINDERS. 
1899. 


e 


Entered,  according  to  Act  of  Congress,  in  the  year  1899,  by 

Greene  V.  Black,  Chicago,  III., 

In  the  Office  of  the  Librarian  of  Congress,  at  Washington,  D.  C. 


PREFACE 


This  book  is  printed  for  the  students  of  Northwestern  Uni- 
versity Dental  School,  and  is  intended  to  fill  an  immediate  and 
pressing  want  in  the  particular  field  to  which  it  is  devoted  —  the 
technical  procedures  in  filling  teeth.  It  consists  of  a  revision  of 
my  lectures  of  last  year  on  that  subject.  The  reprinting  of  these 
was  not  thought  of  until  after  the  beginning  of  the  school  term 
of  this  year  and  the  need  of  it  had  become  especially  manifest. 
The  revision  has,  therefore,  been  done  very  hastily.  The  book 
is  intended  to  answer  a  temporary  purpose  only;  or  until  a  more 
complete  work  can  be  prepared. 

The  absence  of  illustrations  in  the  book  is  well  supplied  in 
the  school  work  by  drawings,  blackboard  illustrations  and  lantern 
slides.  Without  these  much  of  the  matter  would  be  difficult  to 
understand  by  those  unfamiliar  with  the  methods  of  instruction 
employed  in  the  school  ;  but  with  them,  as  employed,  the  need 
of  them  in  the  book  is  reduced  to  the  minimum.  The  book  is 
intended  for  the  students  of  the  school,  not  for  the  general 
profession. 

G.  V.  B. 


THE  TECHNICAL  PROCEDURES  IN  FILLING 

TEETH. 


Introduction. 

Under  the  term   Operative  Dentistry  we  include  all    those 
operations  upon  the  natural  teeth  and  soft  parts  immediately 
connected  with  them  that  are  usually  performed  by  the  dentist. 
But  for  convenience  in  teaching,  and  by  common  consent,  cer- 
tain  operations   are    consigned    to    other    departments.      The 
extraction  of  teeth  belongs  to  Oral  Surgery  ;  the  preparation  of 
natural  teeth,  or  their  roots,  for  crowns  and  bridges,  belongs  to 
crown  and  bridge  work  ;    the  regulation  of  irregular  teeth  to 
Orthodontia,    etc.,    until    today   operative    dentistry   is    pretty 
strictly  confined  to  those  operations  upon  the  natural  teeth  and 
soft  parts  immediately  connected  with  them   for  the  repair  of 
damage  inflicted  by  caries,  to  prevent  further  caries,  and  the 
treatment  of  diseases  resulting  from  exposure  or  death  of  the 
pulps  of  the  teeth.     To  this  is  added  that  group  of  diseases  of 
the  peridental  membrane  beginning  at  the  gingival  border. 

The  subject  matter  in  this  book  will  be  confined  to  a  brief 
presentation  of  the  technical  procedures  in  filling  teeth.  No 
study  of  pathological  conditions  will  be  undertaken  ;  not  even 
of  dental  caries,  further  than  a  study  of  the  position  and  forms 
of  cavities,  and  such  observations  as  may  be  necessary  in  the 
explanation  of  technical  procedures  in  the  preparation  of 
cavities  and  in  filling  teeth.  The  nomenclature  relating  to 
cavities  and  cavity  preparation,  instruments  and  instrumentation, 
will  be  fully  presented. 

Nomenclature. 

Nomenclature  treats  of  the  system  of  naming  things.  Dental 
nomenclature  treats  of  the  terms,  or  names,  used  in  dentistry. 
The  subject  is  of  first  importance,  for  if  we  do  not  know  the 
names  by  which  we  call  things  we  will  be  unable  to  understand 
each  other  in  speaking  of  them.  Every  profession,  business  or 
trade  has  its  special  system  of  naming  things  pertaining  to  it. 


6  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 


t^. 


and  this  nomenclature  must  be  understood  before  the  student 
can  become  proficient.  In  operative  dentistry  this  system  of 
nomenclature  is  very  simple,  and  comprises  but  few  words. 
However,  these  words  are  used  in  a  fairly  wide  range  of  combi- 
nations that  will  be  very  perplexing  to  the  student  who  has  not 
a  good  knowledge  of  them.  Every  student  who  has  arrived  in 
the  senior  class  should  know  them  perfectly  in  their  whole  range 
of  application.  He  should  understand  them  when  spoken  by 
others,  and  be  able  to  use  them  freely  and  correctly  in  his  ordi- 
nary speech.  Otherwise  he  will  be  unable  to  understand  his 
professors  or  fellow-students  as  accurately  as  he  should,  and  thus 
find  his  studies  more  difficult  than  they  otherwise  would  be. 

For  the  most  part  the  words  are  the  same  as  those  used  in 
Dental  Anatomy,  with  which  the  student  should  be  already 
familiar.  But  they  are  applied  differently,  and  to  different 
subjects.      This  new  application    becomes  a  subject   of  study. 

Cavity    Preparation. 

Cavity  preparation  includes  all  those  operations  required  in 
the  removal  of  carious  material  from  cavities  formed  in  the  teeth 
by  decay,  forming  the  cavities  for  the  reception  of  fillings,  and 
such  extensions  and  preparations  as  will  best  fit  the  affected  sur- 
faces of  the  teeth  to  resist  decay  in  future. 

Cavity  Nomenclature. 

Rule  :  Cavities  in  the  teeth  take  the  names  of  the 
surfaces  of  the  teeth  in  which  they  occur. 

We  group  cavities  together  according  as  the  decayed  sur- 
faces are  similarly  situated.  A  further  grouping  may  also  be 
made  into  classes,  each  class  including  those  cavities  that  require 
similar  treatment. 

Cavities  which  occur  in  the  occlusal  surfaces  of  the  teeth  are 
called  occlusal  cavities,  and  occur  in  the  molars  and  bicuspids, 
constituting  a  group. 

Cavities  occurring  in  the  buccal  surfaces  of  the  bicuspids  and 
molars  are  called  buccal  cavities,  and  constitute  a  group. 

Cavities  occurring  in  the  lingual  surfaces  of  the  bicuspids  and 
molars  are  called  lingual  cavities.     They  are  not  frequent. 

Cavities  occurring  in  the  pr03^imate,  or  proximal,  surfaces  of 
the  teeth  are  called  proximate,  oKproximal,  cavities.     These 


J^OMENCLATURE.  7 

are  divided  into  two  groups,  those  occurring  in  the  bicuspids  and 
molars  forming  one  group,  and  those  occurring  in  the  incisors 
and  cuspids  forming  a  separate  group  ;  the  forms  of  the  surfaces 
of  these  two  groups  of  teeth  being  so  different  as  to  require  dif- 
ferences in  consideration  and  treatment.  Each  of  these  groups 
are  again  subdivided  into  mesial  cavities  and  distal  cavities. 

Mesial  cavities  are  those  that  are  in  surfaces  of  the  teeth 
toward  the  median  line  as  we  follow  the  curve  of  the  arch. 

Distal  cavities  are  those  that  are  in  the  surfaces  of  the  teeth 
furthest  from  the  median  line,  following  the  curve  of  the  arch. 

Cavities  occurring  in  the  lingual  surfaces  of  the  upper  incisors 
are  considered  as  a  separate  group,  incisor  lingual  cavities. 
Cavities  occurring  in  the  labial  surfaces  of  the  incisors  and  cus- 
pids are  called  labial  cavities. 

In  addition  to  these  terms,  all  cavities  which  occur  in  the 
axial  surfaces  of  the  teeth  are  called  axial^  surface  cavities. 

In  each  of  these  localities  decay  has  peculiarities  in  its  mode 
of  attack,  or  there  are  differences  of  approach  and  of  instrumen- 
tation in  their  preparation  for  filling  that  render  differences  in 
their  consideration  necessary. 

Cavities  are  also  divided  into  two  groups,  pit  and  fissure 
cavities  forming  one  group,  and  smooth-surface  cavities 
forming  a  second  group.  This  constitutes  a  most  important 
division  of  cavities  of  decay,  calling  for  a  radical  distinction  in 
consideration  and  treatment.  The  pit  and  fissure  cavities  have 
their  beginning  in  minute  faults  in  the  enamel  of  the  teeth  known 
as  pits,  formed  where  three  .or  more  lobes  of  the  teeth  join, 
making  imperfect  closure  of  the  enamel  plates,  as  upon  occlusal 
surfaces  of  the  bicuspids  and  molars  and  the  lingual  surfaces  of 
the  incisors,  or  at  the  endings  of  grooves,  as  upon  the  buccal 
surfaces  of  the  molars.  Fissure  cavities  begin  in  points  of 
imperfect  closure  of  the  enamel  plates  along  the  lines  of  the 
grooves.  These  latter  may  occur  along  the  lines  of  the  grooves 
of  any  of  the  teeth,  but  are  seen  mostly  in  the  occlusal  surfaces 
of  the  bicuspids  and  molars. 

Among  the  groups  of  cavities  all  of  the  occlusal  cavities  in 
the  bicuspids  and  molars  are,  in  their  beginning,  pit  or  fissure 
cavities.  A  part  of  the  buccal  cavities  in  the  molars  are  pit  or 
fissure  cavities  occurring  in  the  buccal  pits  or  fissured  grooves, 
and  part  are  smooth-surface  cavities,  occurring  in  the  smooth 


8  THE   TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

portion  of  the  enamel  of  this  surface  to  the  gingival  of  the  pit, 
or  in  the  gingival  third.  All  buccal  cavities  in  the  bicuspids  are 
smooth-surface  cavities.  All  labial  cavities  in  the  incisors  and 
cuspids  are  smooth-surface  cavities.  All  lingual  cavities  in  the 
upper  incisors  are  pit  or  fissure  cavities,  and  a  few  fissure  cavities 
occur  in  the  occlusal  half  of  the  lingual  surfaces  of  the  molars. 
All  proximate,  or  mesial  and  distal  cavities,  whether  in  the 
molars,  bicuspids  or  incisors,  are  smooth-surface  cavities.  Lin- 
gual cavities  in  the  gingival  half  of  the  molars  are  also  smooth- 
surface  cavities. 

Pit  and  fissure  cavities  occur  in  surfaces  of  the  teeth  that  are 
habitually  clean,  except  as  the  imperfections  of  the  enamel — pits 
and  fissures — afford  places  for  the  lodgment  and  fermentation  of 
d6bris,  which  causes  the  beginning  of  decay.  Therefore,  in 
their  preparation  for  filling  they  require  no  extension  for  preven- 
tion of  recurrence  of  decay,  further  than  a  sufficient  opening  of 
the  cavity  to  completely  uncover  the^  carious  area  and  to  find 
margins  sufficiently  level  and  smooth  to  allow  of  a  good  finish 
of  the  margins  of  the  filling.  Smooth-surface  cavities  occur 
in  positions  in  which  the  surface  of  the  enamel  is  habitually 
unclean,  and  usually  begin  in  the  central  portion  of  the  unclean 
area.  The  injury  to  the  enamel  surface  tends  to  spread  super- 
ficially from  the  central  area  of  first  beginning  toward  the 
margins  of  the  unclean  area.  Therefore,  such  cavities  require 
such  extension  in  their  preparation  for  filling  as  will  include  the 
habitually  unclean  area  within  their  outline  in  order  to  prevent 
the  recurrence  of  caries. 

Classification  of  Cavities. 

In  a  classification  of  cavities  it  is  the  intention  to  group 
together  in  classes  cavities  of  decay  that  require  a  similar  line 
of  treatment  in  order  that  these  may  be  more  closely  asso- 
ciated. 

Class  I. —  Cavities  beginning  in  structural  defects  in  the 
teeth,  as  pits  and  fissures. 

Class  2. —  Cavities  in  the  gingival  third  —  not  pit  cavities  — 
of  the  labial,  buccal  or  lingual  surfaces  of  the  teeth. 

Class  3. —  Cavities  in  the  proximate  surfaces  of  the  incisors 
and  cuspids  which  do  not  involve  the  removal  and  restoration  of 
the  mesial  or  distal  angle. 


NOMENCLATURE.  9 

Class  4. —  Cavities  in  the  proximate  surfaces  of  the  incisors 
and  cuspids  which  do  require  the  removal  and  restoration  of  the 
mesial  or  distal  angle. 

Class  5. —  Cavities  in  the  proximate  surfaces  of  the  bicuspids 
and  molars. 

Class  i. —  Pit  and  fissure  cavities.  These  cavities  are 
located  in  the  occlusal  surfaces  of  the  bicuspids  and  molars,  in 
the  occlusal  two-thirds  of  the  buccal  surfaces  of  the  molars,  in  the 
lingual  surfaces  of  the  upper  incisors,  and  occasionally  in  the 
lingual  surfaces  of  the  upper  molars.  They  are  all  pit  or  fissure 
cavities.  They  occur  in  surfaces  of  the  teeth  that  are  habitually 
clean,  except  as  imperfections  of  the  enamel  in  the  form  of  pits 
or  fissures  afford  an  opportunity  for  the  lodgment  and  fermenta- 
tion of  debris  which  causes  the  beginning  of  decay.  Therefore, 
the  enamel  surface  immediately  about  the  cavity  being  habitually 
clean,  none  of  them  require  extension  for  the  prevention  of  the 
recurrence  of  decay  in  their  preparation  for  filling.  All  that  is 
required  is  to  remove  sufficient  enamel  to  completely  uncover 
the  carious  area  and  to  obtain  margins  sufficiently  level  and 
smooth  to  give  opportunity  for  a  perfect  finish    of  the  filling. 

Classes  2,  3,  4  and  5  are  all  smooth-surface  cavities.  They 
all  occur  in  positions  in  which  the  surfaces  of  the  teeth  are  unclean 
habitually,  and  usually  have  their  beginnings  in  the  central  por- 
tion of  the  unclean  area,  with  a  tendency  of  the  carious  action  to 
spread  superficially  upon  the  enamel  surface.  They,  therefore, 
all  agree  in  requiring  extension  for  the  prevention  of  the  recur- 
rence of  decay  in  such  a  way  as  to  include  within  the  lines  of  the 
enamel  margins  of  the  prepared  cavity  all  of  that  portion  of  the 
surface  especially  liable  to  decay. 

With  respect  to  manipulative  procedures,  each  of  these 
classes  has  its  especial  peculiarities.  For  instance.  Class  2, 
which  includes  all  buccal,  labial  and  lingual  cavities,  requires  in 
most  cases  the  use  of  the  Hatch  clamp  to  extend  the  rubber 
dam  sufficiently  to  the  gingival,  and  the  method  of  instrumenta- 
tion in  their  preparation  is  peculiar  to  them. 

Classes  3,  4  and  5  all  agree  in  requiring  the  use  of  the 
separator  to  give  room  for  finishing,  because  all  are  proximate 
cavities,  but  each  of  these  classes  presents  especial  peculiarities 
in  manipulative  procedure  which  will  receive  attention  later. 


10  THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

Nomenclature  of  the  Intcrna1-f*arts  of  Cavities. 

In  chiving  the  nomenclature  of  the  internal  parts  of  cavities, 
the  rules,  and  illustrations  of  each  rule,  will  be  given.  Students 
should  not  burden  themselves  with  memorizing  these  illustra- 
tions, or  lists,  for  if  they  know  the  rules  and  their  application 
they  can  make  complete  lists  at  any  time.  This  should  be  prac- 
ticed until  the  walls  and  angles  of  any  cavity  can  be  named  at 
sight  without  hesitation. 

Rule  :    The  surrounding  walls  of  a  cavity  take  the 
names    of   those    surfaces    of  the    teeth    adjoining    the 
surface  decayed  toward  w^hich  they  are  placed. 
Illustration  :    Occlusal  cavities  have  — 

A  mesial  wall, 

A  buccal  wall, 

A  distal  wall, 

A  lingual  wall, 
And  — 

A  fifth  wall,  which  is  called  the  pulpal  wall,  or  floor  of 
the  cavity. 

Rule  :  That  wall  of  a  cavity  which  is  to  the  occlusal 
of  the  pulp  and  in  a  plane  at  right  angles  to  the  long  axis 
of  the  tooth,  is  called  the  pulpal  wall  or  floor.  In  case 
the"^pulp  of  the  tooth  is  removed  and  the  cavity  thus 
extended  to  the  floor  of  the  pulp  chamber  it  is  called  the 
sub-pulpal  wall. 

Illustration  :    Buccal  and  lingual  cavities  have  — 

A  mesial  wall, 

An  occlusal  wall, 

A  distal  wall, 

A  gingival  wall. 
And  — 

A  fifth  wall,  called  the  axial  wall. 
Rule  :  That  wall  of  a  cavity  in  an  axial  surface  of  a 
tooth  that  covers  the  pulp  is  called  the  axial  wall.  If 
the  pulp  of  the  tooth  is  removed  the  cavity  is  extended 
to  include  the  pulp  chamber  and  the  wall  takes  the  name 
of  the  w^all  of  the  pulp  chamber. 

Simple  mesial  or  distal  cavities  (proximate  cavities),  in  the 
bicuspids  and  molars,  have  — 


NOMENCLATURE.  11 

A  lingual  wall, 

A  buccal  wall, 

A  gingival  wall, 

An  occlusal  wall, 
And  — 

An  axial  wall. 
But    as   mesial    and  distal    cavities    are    usually   prepared    they 
become    mesio-occlusal    (or   disto-occlusal)    cavities    (complex 
cavities),  the  occlusal  wall   is   missing  and  a  step  is  cut  in  the 
occlusal  surface. 

Rule  :  When  one  of  the  surrounding  walls  of  a  cav- 
ity is  missing  by  reason  of  extension  of  decay,  or  by 
extension  by  cutting  in  the  preparation  for  filling,  so  as  to 
involve  another  surface,  a  complex  cavity  is  formed  and 
the  remaining  walls  extend  to  the  new  surface  involved. 
Therefore,  when  a  mesial  or  a  distal  cavity  in  a  bicuspid  or 
molar  has  involved  the  occlusal  surface,  the  buccal  and  the  lin- 
gual walls  will  terminate  at  the  occlusal  enamel  margin.  The 
axial  wall  will  also  extend  to  the  occlusal  enamel  margin  if  no 
step  has  been  formed,  and  the  occlusal  wall  will  be  missing. 
When  a  step  has  been  formed  its  walls  will  be  named  as  in  a 
simple  occlusal  cavity,  except  that  that  wall  toward  the  cavity 
from  which  the  step  is  formed  will  be  missing. 

Therefore,  mesio-occlusal  (or  disto-occlusal  J  cavities  in  the 
bicuspids  and  molars  have  in  the  proximate  portion  (mesial  or 
distal) — 

A  gingival  wall, 

A  buccal  wall, 

A  lingual  wall. 
And  — 

An  axial  wall. 
In  the  step  portion  — 

A  mesial  Tor  distal)  wall, 

A  buccal  wall, 

A  lingual  wall. 
And  — 

A  pulpal  wall. 
Notice  here   that  in   mesial  cavities  the  mesial  wall  of  the  step 
portion  will   be  missing,  and   in  distal  cavities  the  distal  wall  of 
the' step  portion  will  be  missing. 


12  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

In  a  mesio-  or  disto-occlusal  cavity  in  a  molar  or  bicuspid  in 
which  the  pulp  is  removed,  the  pulpal  and  axial  walls  are 
removed.  The  floor  of  the  pulp  chamber  becomes  the  sub- 
pulpal  wall  of  the  cavity.  This  is  usually  distinct  from  the 
gingival  wall,  because  it  is  on  a  different  level.  Therefore,  a 
mesio-  or  disto-occlusal  cavity  in  a  molar  or  bicuspid  with  pulp 
removed  has  — 

A  buccal  wall, 

A  lingual  wall, 

A  gingival  wall, 

A  distal  (or  mesial)  wall. 
And  — 

A  sub-pulpal  wall. 
Also  some  portions  of  the  mesial  (or  distal)  wall  of  the  pulp 
chamber  will  remain  next  to  the  gingival  wall  as  a  mesial  (or 
distal)  wall.  In  a  bicuspid  or  molar  with  a  single  broad  pulp 
canal  the  pulp  chamber  has  no  floor,  and  of  course  there  will  be 
no  sub-pulpal  wall. 

Proximate  cavities  in  the  incisors  and  cuspids,  on  account  of 
the  wedge-like  or  triangular  form  of  these  surfaces,  have  but 
three  surrounding  walls  — 

A  labial  wall, 

A  lingual  wall, 

A  gingival  wall, 
And  — 

An  axial  wall. 
When  in  incisor  or  cuspid  proximate  cavities  the  incisal  angle 
becomes  involved  so  that  its  removal  is  required,  a  complex 
cavity  is  formed  by  cutting  an  incisal  step.  There  is  in  this  case 
no  change  in  the  naming  of  the  walls  of  the  proximate  portion 
of  the  cavity,  as  no  one  of  the  walls  named  has  been  completely 
removed.     But  the  step  portion  will  have  — 

A  lingual  wall, 

A  labial  wall, 

A  mesial  (or  a  distal)  wall. 
And  — 

A  pulpal  wall. 
Labial  and  lingual  cavities  in  the  incisors  and  cuspids  have  — 

A  mesial  wall, 

A  distal  wall, 


NOMENCLATURE.  13 

A  gingival  wall,  and 
An  incisal  wall. 

Angles  of   Cavities. 

In  naming  cavity  walls  and  angles  the  typical  idea  of  the 
cavity  is  that  of  a  cuboid  space  or  the  form  of  a  box.  And  no 
matter  how  irregular  the  actual  form  of  the  cavity,  its  walls  and 
angles  are  named  as  if  the  form  were  regular. 

Each  simple  cavity  has  two  sets  of  line  angles,  and  one  set  of 
point  angles. 

Rule  :  All  line  angles  are  formed  by  the  junction  of 
two  walls  along  a  line,  and  are  named  by  combining 
the  names  of  the  walls  joining  to  form  the  angle.  They 
are,  therefore,  named  in  two  terms. 

Rule  :  All  point  angles  are  formed  by  the  junction 
of  three  walls  at  a  point,  and  are  named  by  joining  the 
names  of  the  walls  forming  the  angle.  They  are,  there- 
fore, named  in  three  terms. 

In  simple  cavities  one  set  of  line  angles  are  formed  by  the 
junction  of  the  four  surrounding  walls  with  each  other,  and  form 
lines  which  run  from  the  enamel  margin  to  the  floor  or  pulpal 
wall  in  occlusal  cavities,  or  to  the  axial  wall  in  axial  cavities.  A 
second  set  of  line  angles  are  formed  by  the  junction  of  the  sur- 
rounding walls  with  the  floor,  or  pulpal  wall  in  occlusal  cavities, 
or  with  the  axial  wall  in  cavities  in  the  axial  surfaces  of  the 
teeth.  These  are  called  the  pulpal  line  angles,  and  the  axial 
line  angles,  respectively. 

The  point  angles  are  formed  in  those  corners  where  the  one 
set  of  line  angles  meet  the  other  set  at  the  corners  of  the  cavity. 
The  broader  rule  for  naming  angles  to  which  there  is  but  a  single 
exception,  is  : 

Rule  :  All  angles  of  cavities  are  named  by  combin- 
ing the  names  of  the  walls  joining  to  form    the    angle. 

Illustrations  :  (Each  angle  named  is  formed  by  the  junction 
of  the  walls,  the  names  of  which  enter  into  tlie  name  of  the 
angle. ) 

Occlusal  cavities  have  — 

A  mesio-buccal  angle       ^ 

A  mesio-lingual  angle       I  ,  ,  . 

.    ,.        ,  ,         r  ;   ist  set.  )■  Line  angles. 

A  disto-buccal  angle         j  ' 

A  disto-lingual  angle 


14  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

A  bueco-pulpal  angle       -i 

A  lins^uo-pulpal  angle       I      ,  ,  ^^  ,     , 

A  •         1     1         1         Md  set  ^  Pulpal  line  angles. 

A  mesio-pulpal  angle       j  if  s 

A  disto-pulpal  angle         J 
A  mesio-bucco-pulpal  angle     ^ 
A  disto-bucco-pulpal  angle       I 
A  mesio-linguo-pulpal  angle     f  ^'^^^'^  angles. 
A  disto-linguo-pulpal  angle      J 
In  case  the  pulp  is  removed  the  pulpal  wall  is  removed,  and 
the  floor  of  the  pulp  chamber  becomes  the  sub-pulpal  wall  of  the 
cavity,  and  the  pulpal  angles  become  sub-pulpal  angles. 
A  buccal  or  a  lingual  cavity  in  molars  or  bicuspids  has  — 
A  mesio-gingival  angle    ^ 
A  disto-gingival  angle      I 

A  mesio-occlusal  angle     j   ^^^  set  of  line  angles. 
A  disto-occlusal  angle      J 
And  — 

An  axio-gingival  angle     ^ 

An  axio-mesial  angle        I  2d  set  of  line  angles,  or  axial 
An  axio-occlusal  angle     j       line  angles. 
An  axio-distal  angle         J 
An  axio-mesio-gingival  angle    ^ 
An  axio-mesio-occlusal  angle    1 
An  axio-disto-occlusal  angle    [  ^^^^^  angles. 
An  axio-disto-gingival  angle    J 
A  simple  mesial  or  distal  cavity  in  bicuspids  or  molars  has  — 
A  linguo-gingival  angle  ^ 
A  bucco-gingival  angle    j 

A  linguo-occlusal  angle  \  ^^^  ^^^  ^^  ^^^^  ^"g^^s. 
A  bucco-occlusal  angle    J 
An  axio-lingual  angle      -, 

An  axio-occlusal  angle     j  2d  set  of  line  angles  or  axial 
An  axio-buccal  angle        f      Hne  angles. 
An  axio-gingival  angle    J 
An  axio-linguo-gingival  angle  ^ 
An  axio-bucco-gingival  angle  | 
An  axio-linguo-occlusal  angle  j'  ^°^^^  angles. 
An  axio-bucco-occlusal  angle  J 
But  in  mesial  and  distal  cavities  in  the  bicuspids  and  molars  as 
prepared  for  filling,  the  occlusal  wall  is  generally  cut  away  and  a 


NOMENXLATURE.  15 

Step  formed  in  the  occlusal  surface,  forming  a  complex  cavity. 
In  this  case  the  occlusal  wall  is  missing  and  all  of  the  angles 
formed  by  the  junction  of  this  wall  with  others  are  also  missing. 
Then  the  step  in  the  occlusal  surface  has  its  angles  the  same  as 
in  a  simple  occlusal  cavity,  except  that  the  angles  pertaining  to 
the  missing  wall,  mesial  or  distal,  are  also  missing.  This  is  a 
universal  rule  with  complex  cavities. 

Hence  a  mesio  or  disto-occlusal  cavity  has  in  its  mesial  or 
distal  portion  — 

A  bucco-gingival  angle    )   ^^^  ^^^  ^^  ^^^  ^^^j^^^ 


A  linguo-gingival  angle 
An  axio-buccal  angle 


An  axio-lingual  angle       j.  2d  set  of  line  angles. 
An  axio-gingival  angle    j 

An  axio-bucco-gingival  angle  ~i   ^^  . 
.  .    ,.  ^  .^  .     ,     ^ ,     [  Pomt  angles. 

An  axio-lmguo-gmgival  angle  -• 

And  in  the  step  portion  — 

A  mesio-  (or  disto-)  buccal  angle  "t 

A  mesio-  (or  disto-)  lingual  angle  *   ist  set  of  line  angles. 

A  mesio-  (or  disto-)  pulpal  angle  1 

A  linguo-pulpal  angle  l 

A  bucco-pulpal  angle  J  ^d  set  of  line  angles. 

A  mesio-  (or  disto-)  bucco-pulpal  angle  ] 

A  mesio-  (or  disto-)  linguo-pulpal  angle  j  ^^^"^  angles. 
And  a  pulpo-axial  angle  formed  by  the  junction  of  the  pulpal 
wall  of  the  step  with  the  axial  wall  of  the  mesial  or  distal  cavity. 
The  rule  illustrated  in  the  above  is  universal.  A  buccal 
cavity  united  with  an  occlusal  cavity  would  also  have  its  pulpo- 
axial  angle.  The  angles  belonging  to  the  occlusal  wall  of  the 
buccal  cavity  would  be  missing,  and  the  angles  belonging  to  the 
buccal  wall  of  the  occlusal  cavity  would  also  be  missing.  This, 
however,  makes  no  difference  whatever  with  the  naming  of  the 
remaining  angles.  If,  however,  the  pulp  of  the  tooth  is  removed, 
removing  the  axial  and  pulpal  walls,  the  angles  with  these  walls 
are  also  removed  and  the  angles  of  the  pulp  chamber  (sub-pulpal 
angles)  substituted. 

Labial  or  lingual  cavities  in  the  incisors  and  cuspids  have  — 

A  mesio-gingival  angle 

A  disto-gingival  angle  .  ,. 

.  ....         ,         I  ist  set  of  Ime  angles. 

A  mesio-mcisal  angle  ^ 

A  disto-inclsal  angle 


16  THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 


2d  set  of  line  angles. 


An  axio-gingival  angle 

An  axio-mesial  angle 

An  axio-distal  angle 

An  axio-incisal  angle 

An  axio-mesio-gingival  angle 

An  axio-disto-ginofival  angfle     •   ^  . 
.  .  .  °    "^    ,        ?        ^  Point  angles. 

An  axio-mesio-incisal  angle       ; 

An  axio-disto-incisal  angle        J 
Mesial  and  distal  cavities  in  the  incisors  and  cuspids  have, 
on  account  of  their  triangular  form,  but  three  angles  instead  of 
four.     They  have : 

A  labio-gingival  angle  -\ 

A  linguo-gingival  angle        C  ist  set  of  line  angles. 

*An  incisal  angle  J 

An  axio-labial  angle  ^ 

An  axio-lingual  angle  y  2d  set  of  line  angles. 

An  axio-gingival  angle         3 


An  axio-labio-gingival  angle         "\ 

An  axio-linguo-gingival  angle       [-  Point  angles. 

An  axio-incisal  angle  ) 

In  mesial  and  distal  cavities  in  the  incisors  and  cuspids 
involving  the  loss  of  the  incisal  angle,  or  corner  of  the  tooth, 
the  incisal  angle  and  the  axio-incisal  angle  will  be  missing  and 
the  incisal  step  when  formed  will  have  its  set  of  angles.  These 
are  — 

A  pulpo-distal  (or  mesial)  angle  ^ 

A  pulpo-lingual  angle 

A  pulpo-labial  angle 

A  pulpo-axial  angle  J 

A  mesio-  (or  disto-)  labial  angle)      ,  ^  ,.  , 

^       ,.        /,.         1        ,    ^  2d  set  of  Ime  angles. 
A  mesio-  (or  disto-)  Imgual  angle  j 

A  mesio-  (or  disto-)  labio-pulpal  angle 


>  ist  set  of  line  angles. 


1-        N  1-  11         1    /■  Point  angles. 

A  mesio-  (or  disto-)  linguo-pulpal  angle  j 

While  all  angles  are  theoretically  and  actually  present  as 
named,  and  according  to  the  rules  given  and  illustrated,  these 
incisal  steps  are  so  narrow  that  it  would  rarely  be  desirable  to 


*NoTE. —  The  incisal  angle  given  here  is  the  one  exception  to  the  rule  of  naming 
cavity  angles.  If  the  rule  were  followed  strictly  it  would  be  the  labio-lingual  angle,  for 
it  is  formed  by  the  junction  of  these  two  walls.  However,  the  name,  incisal  angle,  can 
not  be  mistaken. 


NOME\XLATURE. 


17 


name  the  point  angles  in  any  directions  for  cavity  preparation  or 
in  cavity  description. 

These  Hsts  of  cavity  angles  may  seem  long  and  tedious,  but 
it  must  be  remembered  that  in  any  directions  for  the  preparation 
of  cavities,  or  in  cavity  descriptions,  very  few  of  them  need  to 
be  mentioned.  However,  the  student  should  be  able  to  under- 
stand just  what  is  meant  when  any  one  of  them  is  mentioned,  or 
be  able  to  name  any  of  them  in  any  cavity.  This  he  will  not  do 
by  memorizing  lists  that  are  given,  but  by  so  learning  the  appli- 
cation of  the  rules  as  to  be  able  to  name  at  once  any  angle  of  any 
cavity. 

Nomenclature  of  Enamel  Margins. 
The   enamel    margin    includes   the   whole   outline   of  the 
cavity  and  is  equivalent  to  the  marginal  lines  of  the  cavity. 
In  this  sense  the  enamel    margin    marks    the   oudines    of  the 
cavity. 

The  Cavo-surface  angle  of  a  cavity,  or  of  the  enamel,  is 
the  angle  formed  by  the  juhction  of  the  wall  of  the  cavity  with 
the  surface  of  the  tooth.  The  cavo-surface  angle  of  a  cavity 
will  ordinarily  be  of  enamel  ;  under  some  unusual  conditions  it 
may  be  of  dentin  ;  or  in  buccal  and  labial  cavities  that  extend 
beyond  the  gingival  line  the  cavo-surface  angle  will  be  of 
cementum.  The  term  cavo-surface  angle  is  used  especially 
when  it  is  desired  to  indicate  the  form  to  be  given  this  angle  in 
any  particular  portion  of  the  enamel  margin,  or  oudine  of  a 
cavity  ;  as,  the  buccal  cavo-surface  angle  was  beveled. 

The  dento-enamel  junction  is  the  line  of  junction  of  the 
dentin  and  enamel  as  it  appears  in  the  walls  of  cavities. 

The  enamel  wall  is  that  portion  of  the  wall  of  a  cavity 
which  consists  of  enamel.  It  includes  the  thickness  of  the 
enamel  from  the  dento-enamel  junction  to  the  cavo-surface 
angle. 

The  dentin  wall  is  that  portion  of  the  wall  of  a  cavity 
which  consists  of  dentin. 

The  Planes  of   the  Teeth  and    the    Inclination    of   Cavity 

Walls. 

The  teeth  have  three  planes  which  may  frequently  be  used  to 
advantage  in  cavity  description,  and  especially  in  speaking  of 
the  inclination  of  cavity  walls. 
2 


18  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

The  horizontal  plane  is  at  right  angles  to  the  long  axis  of 
the  tooth,  and  may  be  supposed  to  cut  through  the  crown  at 
any  point  in  its  length. 

The  axio-mesio-distal  plane,  or  the  mesio-distal  plane, 
passes  through  the  tooth  mesio-distally  parallel  with  its  long 
axis. 

The  axio-bucco-lingual  plane,  or  the  bucco-lingual 
plane,  passes  through  the  tooth  bucco-lingually  parallel  with  its 
long  axis.  In  the  incisors  and  cuspids  this  is  the  labio-lingual 
plane. 

The  inclination  at  which  walls  of  cavities  are  cut,  or  of  the 
dentin  wall  and  the  enamel  wall,  when  each  is  specifically 
mentioned,  is  reckoned  from  these  planes  of  the  teeth.  When 
great  accuracy  of  statement  is  desired  the  inclination  may  be 
given  in  centigrades.  More  generally  the  term  outward 
inclination,  or  inclined  outward,  is  used,  with  some  word 
expressing  degree,  as  slightly,  strongly,  etc.  In  this  use  of 
words  the  wall  of  the  cavity  mentioned  is  always  inclined  away 
from  the  plane  of  the  tooth  in  passing  from  within  outward. 

The  bevel  of  the  cavo-surface  angle  is  always  reckoned 
from  the  plane  of  the  enamel  wall. 

The   Use   of    Divisions   of   the   Surfaces   of   the   Teeth    in 
Cavity   Description. 

Whenever  we  wish  to  indicate  in  words  the  portion  of  a  sur- 
face of  a  tooth  involved  in  decay,  or  the  extent  of  a  cavity,  we 
may  conveniently  do  so  by  an  imaginary  division  of  the  surface 
decayed  into  thirds,  fourths  or  fifths.  This  division  may  be 
mesio-distally  upon  a  buccal,  lingual,  or  occlusal  surface,  or 
occluso-gingivally  upon  a  buccal,  lingual,  mesial,  or  distal  sur- 
face, or  it  may  be  bucco-lingually  upon  an  occlusal,  mesial,  or 
distal  surface.  In  other  words,  the  divisions  may  be  made  upon 
any  one  of  the  planes  of  the  tooth. 

For  instance,  of  a  cavity  in  a  buccal  surface  we  may  say  it 
involves  the  middle  third  mesio-distally  and  the  gingival  third 
occluso-gingivally.  Or  if  the  cavity  is  broader  we  may  say  it 
involves  the  middle  three-fifths  mesio-distally  and  the  gingival 
half  of  the  surface  occluso-gingivally. 

In  this  use  of  words  it  must  be  borne  in  mind  that  when  the 
adverbial   form  is  used,    it  indicates    direction.     Mesio-distally 


CAVITY    PREPARATION.  19 

means  from  mesial  to  the  distal.  Bucco-lingually  means  from 
the  cheek  toward  the  tongue,  etc.  This  use  of  words  is  so  sim- 
ple that  it  should  only  require  mention  to  be  perfectly  under- 
stood. Surgeons  continually  use  this  plan  in  speaking  of  the 
location  of  fractures  of  the  bones.  As,  for  instance,  the  hum- 
erus was  broken  at  the  junction  of  the  middle  and  upper  third, 
or  the  radius  was  broken  in  the  middle  of  the  lower  third,  etc. 
There  is  no  need  of  any  specific  rules  for  this  use  of  words  in 
dividing  the  surfaces  of  the  teeth  in  cavity  descriptions,  as  any 
divisions  intelligently  made  will  be  readily  understood,  and  the 
portions  of  the  surface  involved  quite  accurately  described.  If 
it  is  said  that  a  cavity  in  the  mesial  surface  of  a  first  lower  molar 
extends  from  the  occlusal  surface  to  the  junction  of  the  gingival 
and  middle  third,  and  bucco-lingually  from  the  mesio-buccal 
angle  to  the  junction  of  the  middle  and  lingual  third,  it  should 
be  understood.  The  same  conception  of  the  cavity  should  be 
obtained  if  it  is  said  that  it  occupies  the  buccal  two-thirds  bucco- 
lingually,  or  that  it  occupies  the  buccal  and  middle  third.  There 
is  scarcely  any  limit  to  the  use  that  may  be  made  in  cavity 
descriptions  of  these  divisions  of  the  surfaces  of  the  teeth. 

Cavity   Preparation. 

GENERAL    PRINCIPLES, 

There  are  certain  fimdamental  principles  that  are  general  to 
the  e.xcavation  of  carious  cavities  in  the  teeth,  the  observance  of 
which  will  simplify  and  facilitate  these  operations. 

Order  of    Procedure. 

Obtain,  first,  the  required  outline  form. 

Obtain,  second,  the  required  resistance  form. 

Obtain,  third,  the  required  retention  form. 

Obtain,  fourth,  the  recjuired  convenience  form. 

Fifth,  remove  any  remaining  decayed  dentin. 

Sixth,  correct  the  form  of,  and  smooth  the  enamel  wall,  bevel 
the  cavo-surface  angle,  and  make  the  toilet  of  the  cavity. 

The  careful  observance  of  this  order  of  procedure  by  the 
student  will  greatly  facilitate  his  operations,  lead  to  more  careful 
consideration  of  the  requirements  in  individual  cases,  and  will 
guide  him  to  the  use  of  the  approjiriate  instrument  for  the  differ- 
ent parts  of  the  operation. 


20  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

Outline  Form  is  the  form  of  the  area  of  the  tooth  surface 
to  be  included  within  the  outline,  or  enamel  margins,  of  the  fin- 
ished cavity;  the  laying  out  of  and  cutting  to  these  lines  should 
be  the  first  thing  considered  and  accomplished.  In  all  pit  cavi- 
ties the  outline  of  the  cavity  will  be  found  by  cutting  away  all 
enamel  overhanging  the  decayed  area,  completely  uncovering  it, 
and  following  out  any  sharp  grooves  connecting  with  the  cavity 
to  such  points  as  will  enable  a  perfect  finish  to  be  given  to  the 
margins  of  the  filling  when  placed.  This  should  always  be  done 
before  there  is  any  attempt  made  to  remove  the  decay  from  the 
deeper  parts  of  the  cavity.  As  these  cavities  occur  in  surfaces 
of  the  teeth  that  are  habitually  clean,  except  for  lodgments  in 
the  pits  or  fissures  in  which  the  decay  begins,  no  further  exten- 
sion for  prevention  is  required.  In  this  class  of  cavities  this 
work  is  done  generally  with  chisels  and  the  enamel  hatchets. 
However,  in  the  first  opening  of  pits  in  which  but  little  decay 
has  occurred,  and  in  following  out  fissures  and  grooves,  the  bur 
is  often  the  best  instrument.  In  smooth  surface  cavities,  that  is, 
in  proximate  cavities,  and  buccal  and  lingual  cavities,  which  do 
not  begin  in  pits  or  fissures,  but  which  occur  in  the  central  por- 
tion of  an  area  of  uncleanliness  that  is  habitual,  in  which  the 
superficial  injury  to  the  enamel  tends  to  spread,  the  laying  out 
of  the  outline  form  of  cavities  is  done  upon  a  different  princi- 
ple. In  these  it  is  not  simply  cutting  away  overhanging  enamel 
for  the  exposure  of  the  dentin  already  decayed,  but  the  object 
should  be  to  include  within  the  outline  of  the  cavity  such  por- 
tions of  the  surface  as  are  especially  liable  to  decay  in  the  future. 
As  decay  is  liable  to  occur  upon  surfaces  habitually  unclean,  and 
only  upon  the  unclean  areas,  the  whole  of  the  habitually  unclean 
area  should  be  included  within  the  outline  of  the  cavity.  This 
requires  a  careful  study  of  the  conditions  surrounding  each 
smooth  surface  cavity  and  the  extension  of  the  cavity  outlines  to 
include  the  area  of  the  surface  that  may  have  suffered  superficial 
injury,  or  is  in  danger  of  decay  in  the  future.  This  will  often 
require  that  sound  enamel  and  dentin  be  cut  away  to  obtain  the 
correct  outline  form,  and  is  known  as  extension  for  the  pre- 
vention of  the  recurrence  of  the  decay.  The  study  of  the 
case  should  be  made,  the  outline  determined  upon,  and  the  cav- 
ity cut  to  the  outline  form  required  as  the  first  procedure. 

Resistance  Form  is  that  shape  given  to  a  cavity  intended 


CAVITY    PREPARATION.  21 

to  afford  such  a  seat  for  the  fiUing  as  will  best  enable  it  to  with- 
stand the  stress  brought  upon  it  in  mastication.  Its  importance 
stands  in  direct  relation  to  the  degree  of  the  exposure  of  the 
filling  to  the  occlusion  and  to  the  strength  of  the  closure  of  the 
teeth.  It  is  necessary  to  provide  for  a  force  of  from  one  to  two 
hundred  pounds,  and  in  some  cases  more.  The  resistance  form 
consists  in  a  flat  seat  for  the  filling,  cut  at  right  angles  with  the 
direction  of  the  stress  of  mastication,  or  usually  at  right  angles 
with  the  long  axis  of  the  tooth.  In  occlusal  cavities,  for  example, 
the  floor  or  pulpal  wall  is  to  be  cut  flat  and  all  of  the  surrounding 
walls  should  be  cut  to  definite  angles  with  the  pulpal  wall.  In 
proximo-occlusal  cavities,  in  which  the  greatest  possible  support 
is  needed,  the  gingival  wall  of  the  proximate  portion  is  cut  flat, 
and  in  the  horizontal  plane  of  the  tooth,  and  extended  from 
buccal  to  lingual  into  fairly  definite  corners  or  angles.  The  step 
is  also  given  a  flat  horizontal  seat.  Generally  this  is  easily 
attained  by  the  same  instruments  and  by  the  same  modes  of 
cutting  used  in  gaining  the  outline  form,  if  the  two  objects  are 
held  strictly  in  view. 

Retention  Form  is  the  provision  for  preventing  the  filling 
from  being  displaced.  A  large  part  of  this  is  provided  for  by 
the  resistance  form.  But  it  is  further  required  that  provision  be 
made  that  will  prevent  the  filling  from  being  thrown  out  of  the 
cavity  by  such  lateral  or  tipping  force  as  may  be  brought  against 
it.  All  cavities  should  be  provided  with  ample  retention  form, 
but  this  provision  is  required  in  its  more  perfect  form  in  mesio  or 
disto-occlusal  cavities  in  the  bicuspids  and  molars.  In  these  the 
provision  is  made  in  the  form  of  a  step  cut  into  the  occlusal 
surface,  which  is  more  or  less  dovetailed.  In  most  cavities  the 
retention  form  is  made  by  so  shaping  certain  of  the  opposing 
walls  that  they  will  be  strictly  parallel  or  slightly  undercut  in 
order  that  when  the  filling  material  is  thoroughly  packed  between 
them  it  will  be  securely  held  in  place.  This  is  done  variously  in 
different  situations.  It  is  to  be  looked  to  especially  when  the 
outline  and  resistance  form  of  the  cavity  has  been  developed. 
F"ormerly  pits  and  grooves  were  much  depended  upon  for  this 
purpose,  but  have  proved  delusive,  so  that  latterly  it  has  been 
required  that  the  form  of  the  walls  be  such  as  to  perform  this 
function. 

Convenience  Form,  though  secondary  to  other  points  in 


22  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

the  formation  of  cavities,  should  not  be  neglected.  When  the 
general  form  of  the  cavity  has  been  developed,  modifications  are 
to  be  made  that  will  render  the  form  more  convenient  for  packing 
the  filling  material.  Often  by  cutting  a  wall  away  to  a  certain 
inclination  the  plugger  point  will  reach  some  portion  of  the 
cavity  better,  or  at  a  more  available  angle,  enabling  the  operator 
to  pack  gold  more  certainly  and  more  securely  in  certain  impor- 
tant parts  of  the  cavity.  Also  such  cutting  may  render  the 
filling  so  much  more  convenient  as  to  save  time  and  much  wear 
and  tear  upon  both  patient  and  operator. 

A  second  order  of  convenience  form  is  slight  undercuts  situ- 
ated in  angles  or  other  parts  of  the  cavity  as  starting  points  in 
packing  gold,  or  that  will  hold  the  first  portions  of  the  filling 
material  while  other  portions  are  being  packed,  or  until  the  true 
retention  form  of  the  cavity  has  been  filled.  The  study  of  the 
use  of  these  conveniences  and  the  wise  placing  of  them  is  espe- 
cially important,  as  it  assists  in  starting  the  filling  and  securing 
the  first  portions. 

These  pits  and  grooves  are  usually  placed  in  the  axio-linguo- 
gingival  and  axio-bucco-gingival  angles  of  proximate  cavities,  and 
in  similar  positions  in  other  cavities. 

Removal  of  Remaining  Carious  Dentin. —  Generally 
when  the  cavity  has  been  cut  to  form,  no  carious  dentin  will 
remain.  But  in  the  larger  decays  it  will  often  be  a  question 
whether  or  not  the  pulp  will  be  exposed  when  all  decayed  den- 
tin overlaying  it  is  removed.  It  is  especially  an  object  that  we 
do  not  cut  toward  the  pulp  until  the  cavity  is  otherwise  well  pre- 
pared, for  the  reason  that  if  a  pulp  exposure  is  found  the  cavity 
shall  be  fully  cleaned  and  ready  for  the  immediate  treatment  of 
the  pulp  in  any  way  indicated.  Then  when  this  stage  in  cavity 
preparation  has  been  reached,  the  remaining  softened  dentin  is 
carefully  and  completely  removed  with  broad  spoon  excavators, 
usually  with  the  20-9-12.  It  will  often  be  required  that  the  pulp 
of  a  tooth  be  exposed  for  the  purpose  of  making  an  application 
to  destroy  it.  In  all  of  these  cases  the  overhanging  enamel 
should  be  removed  and  the  walls  of  the  cavity  completely  cleaned 
and  so  formed  as  to  safely  hold  the  temporary  filling,  before  cut- 
ting toward  the  pulp.  When  all  of  this  has  been  done  and  after 
the  rubber  dam  is  securely  in  place,  lift  off  the  remaining  decay 


CAVITY    PREPARATION.  23 

with  spoon  excavator  20-9-12,  laying  the  pulp  bare.  If  this  is 
properly  done  very  little  pain  is  induced. 

Finishing  the  enamel  ^vall  and  beveling  the  cavo-sur- 
face  angle  of  the  enamel  is  the  last  cutting  done  in  the  prepara- 
tion of  a  cavity.  This  should  always  be  done  with  the  rubber 
dam  in  place  and  with  all  provisions  made  for  the  immediate 
placing  of  the  filling  material. 

The  cavo-surface  angle  of  the  cavity  in  every  part  of  its 
outline  should  receive  especial  attention.  The  plane  of  the 
enamel  wall  should  be  as  nearly  as  practicable  in  the  line  of  the 
length  of  the  enamel  rods,  or  such  as  will  certainly  cut  more 
from  the  outer  than  the  inner  ends  of  the  rods,  and  should  be 
made  smooth  by  a  light  planing  motion  of  a  sharp  chisel  or 
enamel  hatchet,  the  motion  being  in  line  with  the  length  of  the 
margin.  When  this  has  been  satisfactorily  accomplished  the 
cavo-surface  angle  of  the  enamel  should  be  cut  to  a  distinct  bevel 
outward,  also  by  a  planing  motion  of  the  chisel,  enamel  hatchet  or 
the  gingival  margin  trimmer,  used  very  lightly.  The  depth  of 
this  bevel  should  generally  not  include  more  than  one-fourth  the 
thickness  of  the  enamel  wall.  The  angle  of  the  bevel  should  be 
from  six  to  ten  centigrades  from  the  plane  of  the  enamel  wall. 
The  object  is,  first,  to  cut  away  any  loose  ends  of  enamel  rods 
that  might  afterward  fall  away  and  render  the  margin  imperfect  ; 
and,  secondly,  to  strengthen  the  cavo-surface  angle  of  the  enamel 
as  a  safeguard  against  possible  checking  in  packing  the  filling 
material. 

In  this  last  work,  two  things  should  be  held  closely  in  view. 
The  cavo-surface  angle  of  the  enamel  is  friable  and  readily 
broken  by  violence,  and  beveling  will  materially  lessen  this 
liability.  But  the  marginal  angle  of  the  filling  material  which 
covers  the  bevel  must  not  be  made  too  thin  by  too  great  a  be\el 
of  the  cavo-surfiice  angle  of  the  enamel.  If  so,  it  will  have  no 
strength  and  will  tend  to  roughen  and  in  this  way  render  the 
margin  imperfect.  Therefore,  the  bevel  of  the  cavo-surface 
angle  of  the  enamel  must  not  be  too  great. 

Finally,  the  toilet  of  the  cavity  is  to  be  made.  This  con- 
sists in  freeing  all  of  its  surfaces  from  the  chips  and  dust  that 
have  accumulated  during  the  excavation.  The  bulk  of  this  is 
done,  of  course,  with  the  chip  blower  during  the  progress  of  the 
excavating.      But   there   will   remain   some   fine  dust    upon    the 


24  THE    TECHNICAL    PROCEDURES    IN   FILLING    TEETH. 

walls  and  margins  that  can  not  be  removed  in  this  way.  It  is 
not  well  to  wash  this  with  any  known  liquid,  for  even  with  the 
use  of  pure  alcohol,  and  after  drying  with  the  air  syringe,  some- 
thing will  be  left  coating  the  walls  which  injures  them  for  the 
purposes  intended.  The  best  thing  yet  devised  is  thorough 
wiping,  or  sweeping,  of  all  parts  of  the  cavity  with  absorbent 
cotton  or  with  bits  of  punk  held  in  the  pliers.  This  should  be 
well  done  and  then  the  cavity  is  ready  for  filling. 

Rule  :  No  moisture  of  any  kind  whatever  should 
enter  a  cavity  after  the  last  of  the  cutting  is  done,  and  if 
by  any  accident  a  portion  of  the  cavity  should  become 
w^et,  it  should  be  dried  thoroughly  and  then  that  portion 
that  has  been  damp  should  be  freshened  by  cutting  away 
the  surface. 

Instruments  and  Instrumentation. 

The  cutting  instruments  required  for  preparing  cavities  have 
been  adopted  after  long  and  careful  study  of  the  needs  of  stu- 
dents in  school  work.  The  set  has  been  arranged  especially 
with  reference  to  teaching  methods  of  preparing  cavities,  and 
for  facilitating  the  actual  work.  It  is  such  as  will  be  best  in 
learning  to  do  these  difficult  operations,  and  it  is  to  this  end 
that  they  are  adopted. 

Each  of  the  names  we  apply  to  instruments  has  a  definite 
meaning.  They  are  descriptive  of  the  uses,  as  excavator,  plug- 
ger,  separator,  or  the  manner  of  use,  as  hand  plugger.  They 
describe  the  form  of  blades  of  cutting  instruments,  as  hatchet, 
hoe,  spoon,  or  they  describe  the  form  of  the  shank,  as  contra- 
angle,  bin-angle,  cow's-horn  plugger. 

Note  here  especially  that  there  are  four  classes  of  names. 
First,  those  which  denote  the  purpose,  which  we  call  order 
names,  as  plugger,  excavator  ;  second,  those  which  denote 
position  or  manner  of  use,  sub-order  names,  as  hand  or  mal- 
let plugger,  enamel  hatchet  ;  third,  those  which  describe  the 
form  of  point,  class  names,  as  hatchet,  spoon  ;  and  fourth, 
those  which  describe  the  form  of  the  shank,  sub-class  names, 
as  bin-angle,  contra-angle,  cow's-horn  or  spiral. 

The  names  we  apply  to  instruments  are  classified  as  follows  : 
Order  names. 
Sub-order  names, 


INSTRUMENTS    AND    INSTRUMENTATION.  25 

Class  names, 
Sub-class  names. 
Order  names  denote   purpose,    and   answer   the   question 
' '  what  for. ' ' 

Examples  :  Excav^ators, 
Pluggers, 
Separators, 
Scalers, 
Clamps,  etc. 
Sub-order   names  denote  the  manner  or  position  of  use, 
and  answer  the  question  ' '  where  or  how  used  ?  ' '  and  are  usually 
a  suffix  to  an  order  name. 

Examples  :  Hand  mallet. 
Hand  plugger, 
Mallet  plugger, 
Enamel  hatchet, 
Push  scaler. 
Pull  scaler, 
Molar  clamp,  etc. 
Class  names  are  descriptive  of  the  working  point  of  the 
instrument. 

Examples  :  Hatchet, 
Hoe, 
Spoon, 
Discoid, 
Cleoid, 

Serrated  plugger. 
Smooth  plugger,  etc. 
These  are  also  used  as  suffixes  to  order  names,  as  in  the  last 
two  ;  and  also  as  in  hatchet  excavator,  hoe  excavator,  etc. 

Sub-class  names  describe  the  shape  of  the  shank  of  the 
instrument. 

Examples  :  Mon-angle, 
Bin-angle,  ' 
Triple-angle, 
Contra-angle, 
Cow-horn, 
Bayonet,  etc. 
These  names  are  often  combined  for  more  complete  descrip- 
tions of  the  instruments  named,  thus  :  Mon-angle  excavator,  or, 


26  THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

mon-angle  hatchet  excavator,  bin-angle  spoon  excavator,  etc. 
In  these  combinations  each  name  is  descriptive  of  some  part  of 
the  instrument,  or  of  its  uses.^ 

In  addition  to  these  we  have  adopted  formula  names  -for  the 
cutting  instruments  that  describe  each  individual  instrument  so 
accurately  that  when  learned  each  one  will  be  known  when  its 
formula  name  is  spoken.  This  is  necessary  in  order  that  a 
teacher  may  be  understood  when  speaking  of  the  uses  of  par- 
ticular instruments  in  lectures,  or  that  students  may  understand 
the  directions  of  demonstrators  in  the  infirmary. 

These  formula  names  are  made  upon  the  same  principle  as 
that  used  by  the  carpenter  in  naming  his  chisels  or  augers,  as 
half-inch  chisel,  one-inch  chisel,^  three-quarter-inch  auger,  etc. 
But  for  us  to  sufficiently  describe  the  point  of  an  excavator  so 
that  we  will  know  the  particular  instrument  at  sight,  it  is  neces- 
sary that  we  give  three  measurements.  We  give  first  the  class 
name,  as  hatchet,  hoe,  spoon,  etc. ,  and  then  give  the  formula  of 
the  point,  or  working  part.  This  formula  consists  of  the  meas- 
urement, first,  of  the  width  of  the  blade  in  tenths  of  a  milli- 
meter ;  second,  of  the  length  of  the  blade  in  millimeters  ;  third, 
the  angle  of  the  blade  with  its  shaft  or  handle,  in  centigrades, 
or  hundredths  of  the  circle.  Note  particularly  that  the  width 
and  length  make  up  the  size  of  the  blade.  Also,  in  order  that 
the  individual  instruments  of  the  set  may  be  easily  learned  and 
remembered  we  confine  the  set  to  a  regular  order  of  sizes  and 
angles  of  blade  that  will  give  a  sufficient  variety  of  forms. 

The  set  of  cutting  ihstrurnents  consists  of  two  lists  of 
formulae.  One  of  these  we  call  ordinaries,  and  the  other 
specials.  Aside  from  the  regular  formula  lists  we  have  four 
instruments  that  are  not  made  upon  these  formula  lines.  These 
we  call  side  instruments. 

Dental    Instrument   Gauge. 

This  gauge  for  dental  instruments  is  used  especially  in  the 
measurement  of  excavators,  pluggers  and  burs.  It  is  in  the 
metric  system.     It  is  used  as  follows  : 

I.  Measure  the  width  of  the  blade  in  the  slot  numbered  from 
o  to  50,  which  gives  the  width  in  tenths  of  a  millimeter.  This  is 
the  first  figure  of  the  formula. 

*  Only  the  nomenclature  and  the  uses  of  instruments  will  be  given  here.  The  phi- 
losophy of  instrument  forms  has  been  well  presented  in  the  freshman  year. 


INSTRUMENTS    AND    INSTRUMENTATION. 


27 


blade,  no  more  and  no  less 
up  the  formula. 


2.    Measure    the    length    of    the 
blade  in  the  gradations  on  the  prin- 
cipal  shaft,   which  gives   the  length 
of  the  blade  in  millimeters.     This 
is    the  second    figure  of  the   for- 
mula. 

3.  Measure  the  angle  of  the 
blade  with  its  shaft  by  laying  the 
handle  of  the  instrument  on  the  main 
shaft  of  the  gauge,  parallel  with  the 
lines,  and  bringing  the  blade  (turned 
toward  the  small  numbers)  parallel 
with  one  of  the  gradations  of  the  cir- 
cular head.  This  will  give  the  angle 
of  the  blade  with  the  shaft  in  centi- 
grades  or  hundredths  of  the  circle. 
This  gives  the  third  figure  of  the 
formula. 

These  formulee  are  stamped  on 
the  handles  of  the  excavators. 

Plugger  points  may  be  meas- 
ured and  designated  in  a  similar 
manner. 

The  diameter  of  burs  may  be 
obtained  by  measurement  in  the 
slot. 

The    Ordinaries. 

The  set  of  ordinaries  is  made 
up  of  hoes  and  hatchets  ;  nine 
hatchets  and  nine  hoes,  or  eighteen 
instruments.  In  these  there  are 
three  widths  and  lengths  of  blade 
(three  sizes)  and  three  angles  of 
The  measurements  of  these  make 


28 


THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 


Formulae  of  the  Ordinaries 

—  Hatchets  and  Hoes. 

Sizes, 

Angles. 

12 

wide, 

5  long. 

-    6 

centigrades  angle. 

8 

3      " 

6 

6 

2         " 

6 

12 

5      " 

12 

8 

3      " 

12 

6 

2         " 

12 

12 

5      " 

23 

<  (     '            ( ( 

8 

3      " 

23 

6 

2         " 

23 

Note  particularly  that  the  sizes  are  the  same  in  each  of  the 
three  angles,  and  that  there  are  but  three  sizes  and  but  three 
angles,  all  told,  of  these  ordinaries,  and  also  that  the  formulae  are 
the  same  for  hatchets  and  hoes.  There  are  nine  hatchets  and  nine 
hoes  in  the  set.  Or  there  is  a  large  size,  a  middle  size  and  a 
small  size  in  three  angles.  When  these  facts  are  in  mind  and 
they  have  been  handled  a  few  times,  one  should  be  able  to  name 
each  instrument  at  sight.  To  assist  in  this  the  formula  of  each 
instrument  is  stamped  on  the  handle,  so  that  each  of  the  three 
sizes  in  each  of  the  three  angles  can  easily  be  picked  out  and 
examined.  In  learning  to  read  the  points,  or  to  name  them  at 
sight,  one  should  pick  out  by  aid  of  the  figures  upon  the  han- 
dles the  three  sizes  of  each  angle  of  the  hatchets  and  lay  them 
together;  then  do  the  same  with  the  hoes;  then  change  them 
and  lay  together  each  size  of  the  three  angles  and  compare  them 
in  this  relation  .to  each  other.  After  doing  this  a  few  times  one 
should  be  able  to  pick  out  any  instrument  without  referring  to 
the  formula  upon  the  handle.  We  call  them  hatchet  12-5-6, 
hatchet  8-3-12,  hoe  8-3-12  or  hoe  8-3-23,  etc. 

The  set  of  ordinaries  have  been  so  called  because  they 
include  the  forms  that  have  been  most  used  by  dentists  in  the 
past.  Instruments  similar  to  them,  but  less  perfecdy  assorted, 
are  found  in  every  dentist's  operating  case.  The  smaller  sizes 
of  this  set  are  used  but  little  except  in  the  preparation  of  cavi- 
ties in  the  incisor  teeth,  and  mostly  in  the  final  shaping  of  the 
walls  and  angles  of  these  cavities  after  they  have  been  opened  by 
other  instruments. 

The  hoe  12-5-6  used  as  a  chisel  is  the  most  useful  instrument 
in  opening  cavities  in  the  incisors,  especially  for  cutting  away 


INSTRUMENTS    AND    INSTRUMENTATION.  29 

the  labial  enamel  margins  until  the  proper  form  has  been 
reached.  The  hatchet  12-5-6  performs  the  same  office  for  the 
gingival  wall.  Very  often,  in  the  more  delicate  of  this  cutting, 
the  middle  sizes,  i.  e. ,  hoe  8-3-6  and  hatchet  8-3-6,  will  serve 
better  and  in  many  cases  it  will  be  found  more  convenient  to  use 
the  same  sizes  in  the  angle  of  12  centigrades,  or  the  hoe  12-5- 12 
and  hatchet  12-5- 12,  etc.,  or  the  sizes  8-3.  The  smallest  size, 
or  6-2-6  and  12,  are  used  only  in  shaping  the  internal  parts  of 
cavities  in  the  incisors  and  cuspids,  and  especially  in  squaring 
out  the  axial  line  angles  of  these  cavities  so  that  they  are  sharp 
and  definite.  The  angles  of  23  are  convenient  for  reaching  cer- 
tain points  not  easily  reached  with  the  angles  6  and  12,  but  are 
used  much  less  than  the  latter. 

The  Specials. 

The  set  of  specials  are  so  called  because  each  instrument  is 
designed  for  a  special  use.  The  formulee  of  this  set  are  upon  a 
different  set  of  sizes,  the  plan  of  measurement  being  the  same. 
In  these  are  also  three  widths  and  lengths  of  blade,  three  sizes 
and  one  angle  of  blade  of  12  centigrades  for  all  except  the 
binangled  chisels,   which  are  6  centigrades  angle. 

Formulas  of  the  Specials. 

Straight  chisel,  20,  width  only  given. 

Straight  chisel,  15. 

Straight  chisel,  10. 

Binangle  chisel,  20-9-6. 

Binangle  chisel,  15-8-6. 

Binangle  chisel,  10-6-6. 

Enamel  hatchets,  rights  and  lefts,  20-9-12. 

Enamel  hatchets,  rights  and  lefts,  15-8- 12. 

Enamel  hatchets,  rights  and  lefts,  10-6- 12. 

Spoons,  rights  and  lefts,  20-9-12. 

Spoons,  rights  and  lefts,  15-8- 12. 

.Spoons,  rights  and  lefts,  10-6- 12. 

Gingival  margin  trimmers,  rights  and  lefts,  20  (95)-9-i2.* 

Gingival  margin  trimmers,  rights  and  lefts,  20  (8o)-9-i2. 

*  NoTK.^Whcii  it  becomes  necessary  to  designate  the  angle  of  tlie  cutting  edge  of 
an  instrument  with  its  shaft,  it  is  done  by  sliding  it,  without  rotation,  to  the  left,  still 
keeping  it  parallel  with  the  longitudinal  lines,  until  the  angle  of  the  cutting  edge  corre- 
sponds with  one  of  the  lines  of  the  larger  numbers  to  the  left.  This  number  is  then 
entered  in  brackets  following  the  width  number.  When  not  so  designated  the  cutting 
edge  is  at  right  angles  with  the  length  of  the  blade. 


30  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

Formulas   of   Side    Instruments. 

Hatchets,  5-3-28  and  3-2-28. 

Discoid,  20,  and  cleoid,  20. 

Of  the  three  last  groups  of  specials,  the  enamel  hatchets 
are  rights  and  lefts,  because  of  the  form  of  the  bevel  of  the  cut- 
ting edge.  The  spoons  and  gingival  margin  trimmers  are 
made  rights  and  lefts  by  the  curve  of  the  blade.  All  the  specials 
are  designed  for  special  work.  They  are  used,  except  the  small- 
est size  of  the  spoons,  almost  exclusively  in  the  bicuspids  and 
molars,  and  in  these  they  should  be  used  for  almost  all  of  the 
work  of  excavating. 

The  chisels  and  enamel  hatchets  are  used  for  chipping  away 
the  enamel  in  opening  cavities  in  the  bicuspids  and  molars,  and 
in  cutting  the  outlines  to  the  required  form.  The  enamel 
hatchets  are  used  especially  for  cutting  away  the  buccal,  lingual 
and  gingival  walls  of  proximate  cavities  in  these  teeth  and  in 
shaping  them.  Also,  both  the  chisels  and  enamel  hatchets  are 
used  in  the  final  shaping  of  the  enamel  wall  and  in  beveling  the 
cavo-surface  angle  of  the  enamel. 

The  gingival  margin  trimmers  are  used  for  only  the  one 
purpose  of  beveling  the  cavo-surface  angle  of  the  enamel  along 
the  gingival  wall  of  proximate  cavities  in  the  bicuspids  and 
molars.  For  this  purpose  one  pair  has  the  edge  cut  at  an  angle 
of  80  centigrades  with  the  shaft,  which  is  right  for  beveling  the 
gingival  cavo-surface  angle  of  the  enamel  in  mesial  cavities,  and 
the  other  pair  has  the  edge  cut  at  an  angle  of  95  centigrades 
with  the  shaft,  which  fits  them  for  beveling  the  gingival  cavo- 
surface  angle  of  the  enamel  in  distal  cavities. 

The  spoons  are  used  for  scooping  out  softened  material 
(carious  dentin)  from  the  deeper  parts  of  carious  cavities. 
They  should  be  used  only  after  the  walls  have  been  cut  to  form 
by  other  instruments.  They  are  not  at  all  suited  to  cutting 
hard  dentin. 

Side  Instruments. —  There  are  four  side  instruments  in  the 
set.  They  are  called  side  instruments  because  their  formulae  do 
not  coincide  with  those  of  either  of  the  other  sets.  Of  these 
the  discoid  (disc  like)  performs  a  service  similar  to  the  spoons, 
i.  e. ,  the  removal  of  softened  dentin  from  the  deeper  parts  of 
the  cavity  after  the  walls  have  been  cut  to  form  by  other  instru- 


INSTRUMENTS    AND    INSTRUMENTATION.  31 

ments.  In  positions  in  which  the  access  is  direct  it  is  a  more 
convenient  instrument  than  the  spoons,  though  generally  the 
spoons  are  better. 

The  cleoid  is  used  most  for  trimming  out  the  angles  of  pulp 
chambers  in  order  to  reach  the  canals  with  the  broach  more 
readily,  especially  the  canals  in  the  mesio-buccal  roots  of  the 
upper  molars  and  the  mesio-buccal  and  mesio-lingual  angles  in 
the  lower  molars. 

The  two  hatchets,  5-3-28  and  3-2-28,  are  used  only  for  the 
purpose  of  undercutting  the  incisal  angle  of  proximate  cavities 
in  the  incisors  and  cuspids  for  the  purpose  of  obtaining  retention 
form.  They  are  designed  for  this  special  purpose  and  are  used 
for  nothing  else  whatever. 

Instrument  Grasps  and  Rests. 

The  manner  of  holding  instruments  in  performing  dental 
operations  is  very  important.  There  are  two  principal  grasps  : 
The  pen  grasp  and  the  thumb  and  palm  grasp,  with  modifica- 
tions of  both. 

The  pen  grasp  is  used  for  most  operations.  As  implied  in 
the  term,  the  instrument  is  held  in  the  fingers  in  the  position,  or 
with  the  same  grasp  with  which  we  would  hold  a  pen,  and  the 
manipulation  is  carried  on  with  the  instrument  held  in  that  posi- 
tion, whether  in  cutting  with  an  excavator  or  packing  gold  with  a 
plugger.  Perhaps  nine-tenths  of  these  operations  should  be  done 
with  the  instruments  held  in  that  way.  Occasionally  positions 
are  found  in  which  the  operation  may  be  much  facilitated  by  a 
modification  of  this  grasp,  made  by  bending  the  fingers  into,  or 
nearly  into,  the  palm  of  the  hand,  thus  inverting  the  position  of 
the  instrument  so  that  it  points  directly  at  right  angles  to  the 
length  of  the  arm.     This  is  called  the  inverted  pen  grasp. 

In  the  use  of  these  grasps  certain  rests  for  the  fingers  should 
be  sought  and  practiced  until  they  are  correctly  obtained  without 
especial  thought.  By  the  use  of  these  rests  operations  can  be 
much  more  accurately  performed  than  without  them,  and  they 
gready  limit  the  danger  of  injury  to  the  patient  by  slips  of  the 
instrument. 

The  rests  are  generally  made  by  placing  the  third  or  fourth 
finger,  preferably  the  third,  upon  the  teeth  of  the  same  jaw  in 
which  the  tooth  operated  upon  is  situated.      In  operating  upon 


32  THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

the  molars  the  rest  will  be  upon  the  anterior  teeth.  When 
operating  upon  the  anterior  teeth  the  rest  will  be  found  on  either 
side  of  the  tooth  operated  upon.  Any  effort  to  use  the  teeth  in 
the  opposite  jaw  for  a  rest  will  be  found  very  unsatisfactory,  on 
account  of  the  movements  of  the  lower  jaw  changing  the  rela- 
tion of  the  rest  and  the  tooth  operated  upon.  Rests  upon  the 
soft  tissues  should  be  avoided  as  much  as  possible,  because  they 
are  unreliable  at  best,  and  always  unsteady. 

In  the  thumb  and  palm  grasp  the  shaft  of  the  instrument 
is  held  in  the  palm  of  the  hand  in  such  manner  as  to  oppose  the 
working  point  to  the  thumb,  and  the  thumb  of  the  same  hand  is 
placed  either  upon  the  tooth  upon  which  the  operation  is  per- 
formed, or  upon  an  adjacent  one,  to  steady  the  instrument  and 
to  oppose  a  counter  pressure.  This  grasp  is  not  oft;^n  useful, 
except  when  unusual  force  is  to  be  applied.  Neither  can  it  be 
used  successfully  in  very  many  positions.  However,  there  are 
certain  operations  in  which  its  use  is  very  desirable,  and  each 
student  should  learn  these  by  careful  practice.  It  is  especially 
useful  with  the  Case  cleaver  in  removing  the  enamel  from  the 
teeth  for  fitting  bands  for  crowns,  and  may  be  used  upon  any  of 
the  upper  anterior  teeth,  and  often  upon  the  first  and  second 
molars. 

The  thumb  and  palm  grasp  may  be  used  very  successfully 
with  the  chisel  in  opening  cavities  in  any  of  the  upper  anterior 
teeth,  and  as  far  back  as  the  first  molars,  though  only  in  a  limited 
number  of  positions.  The  requirement  is  that  when  the  chisel  is 
grasped  in  the  palm  of  the  hand  and  the  thumb  of  the  same  hand 
applied  to  the  tooth  operated  upon,  or  the  one  next  to  it,  the 
instrument  will  come  into  position  to  be  used  effectively.  When 
these  positions  are  found  the  chisel  can  be  used  much  more 
effectively  than  is  possible  with  the  pen  grasp.  It  is  therefore 
desirable  that  this  grasp  be  practiced  at  every  opportunity,  and 
its  use  extended  as  much  as  possible. 

Sharpening  Instruments. 

Nothing  in  dental  practice  is  more  important  than  the  care 
of  the  cutting  edges  of  instruments.  No  man  ever  yet  became 
a  good  and  effective  dentist  until  after  he  had  learned  to  keep  his 
cutting  instruments  sharp.  It  is  simply  impossible  to  effectively 
prepare  cavities  for  filling  without  sharp  instruments.     The  dental 


INSTRUMENTS    AND    INSTRUMENTATION.  33 

Student  who  can  not,  or  will  not,  learn  to  keep  the  edges  of  his 
cutting  instruments  in  good  condition  had  better  quit  and  go 
home,  for  he  will  not  succeed  as  a  dentist.  A  good  stone  is  a 
necessity.  It  is  of  first  importance  that  the  stone  be  very  hard. 
Our  instruments  are  small,  and  if  we  attempt  to  use  a  soft  stone 
the  point  will  catch  and  ruin  both  the  edge  of  the  instrument 
and  the  surface  of  the  stone.  The  stone  should  never  be  smaller 
than  I  ^2  by  5  inches.  A  stone  somewhat  larger  is  much  better, 
but  a  smaller  stone  is  a  nuisance.  A  hard  Arkansas  stone  is 
best.  The  hardness  should  be  especially  looked  to  in  selecting 
a  stone.  The  care  of  the  stone  is  very  important.  It  should  be 
thoroughly  oil-soaked  and  then  wiped  off.  It  may  then  be  used 
dry  or  with  oil,  but  however  used  it  should  be  wiped  off  clean 
with  oil  upon  a  cloth  after  using.  If  this  be  not  done  the  stone 
will  soon  fill  up  with  the  steel  cuttings  and  it  will  fail  to  cut  when 
the  effort  is  made  to  grind  with  it.  These  steel  cuttings  are 
removed  from  the  stone  by  the  oil  and  the  cloth.  If  the  face  of 
the  stone  becomes  marred  or  unlevel  from  use,  it  may  be  refaced 
by  rubbing  it  on  a  sheet  of  emery  paper  laid  flat  upon  a  smooth, 
level  table  or  board.  The  facing  should  be  finished  on  the  finest 
grade  of  emery  paper.  A  good  stone  should  last  a  lifetime  if 
well  taken  care  of 

The  cutting  edges  of  the  excavators  should  be  ground  care- 
fully, observing  that  the  correct  bevel  of  the  edge  be  maintained 
and  that  the  edge  is  kept  straight.  To  this  end  instruments 
should  be  carefully  applied  to  the  stone  and  the  correct  position 
maintained  throughout  the  back  and  forth  motions  of  grinding. 

The  spoons  and  discoids  are  ground  by  placing  them  on  the 
stone  so  that  the  motion  in  grinding  will  be  parallel  with  the 
length  of  the  cutting  edge,  and  during  each  stroke  the  instru- 
ment is  rotated  upon  its  edge  in  such  a  way  that  every  part  of 
the  semi-circular  edge  will  come  against  the  stone  in  some  part 
of  each  motion.     This  is  easily  done  after  a  little  practice. 

Care  as  to  heating  the  instrument  points  while  grinding  is 
very  important.  If  heavy  pressure  is  made  and  the  instrument 
moved  rapidly  upon  the  stone,  enough  heat  will  be  quickly 
developed  to  draw  the  temper  of  the  steel  and  ruin  the  instru- 
ment. It  is  well  for  the  beginner  to  place  one  finger  upon  the 
point  of  the  instrument  while  grinding,  that  he  may  feel  the  heat 
develop,  until  he  has  learned  to  judge  accurately  of  this  danger, 
3 


34  THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

Use  of  the  Dental  Engine. 

The  dental  engine  has  in  recent  years  become  an  important 
instrument  in  operative  dentistry.  It  is  used  for  certain  parts  of 
the  work  of  excavating  cavities,  for  trimming  fiUings  to  form 
after  they  have  been  inserted,  and  a  large  amount  of  the  work 
of  polishing  is  best  done  with  it.  For  these  several  purposes 
engines  should  be  equipped  with  certain  sizes  and  forms  of 
excavating  burs,  a  few  sizes  and  forms  of  finishing  burs,  stones 
for  grinding  and  sandpaper  disks  of  different  grades  of  fineness, 
rubber  disks  for  carrying  polishing  powders,  etc. 

In  excavating,  the  bur  is  nowadays  indispensable,  and  yet  but 
a  small  part  of  the  excavating  should  be  done  with  burs.  The 
tendency  among  students  is  to  continually  use  the  bur  too  much 
and  to  use  it  in  improper  places. 

The  forms  of  bur  most  useful  are  what  are  known  as  the 
inverted  cone  bur  and  the  fissure  bur.  Round  burs  are  not 
often  used  to  advantage,  and  yet  there  are  certain  definite  pur- 
poses requiring  round  burs. 

The  sizes  of  burs  are  very  important.  With  the  dental 
engines  with  which  we  are  supplied  no  large  burs  can  be  used  to 
advantage  for  the  reason  that  the  motion  is  conveyed  by  a  cable 
which  allows  large  burs  to  jump  and  chatter.  Cord  engines 
give  to  the  bur  a  much  smoother  motion  and  better  cutting 
power,  but  are  not  regarded  as  so  convenient.  Practically  none 
of  them  have  sufficient  power  to  run  a  large  bur  to  advantage. 
For  our  use,  then,  burs  for  excavating  that  are  over  one  and 
one-half  millimeters  in  diameter  should  not  be  used  at  all.  The 
most  useful  burs  are  one  millimeter  and  less  in  diameter.  The 
round  bur  is  used  only  for  the  one  purpose  of  opening  pit  cavi- 
ties in  which  decay  has  only  just  begun.  For  this  purpose 
round  burs,  from  a  little  less  than  one  millimeter  to  one  and  a 
half  millimeters  in  diameter,  should  be  used  by  placing  them  in 
the  pit  while  in  motion  and  swaying  the  hand-piece  to  and  fro  so 
as  to  rotate  the  bur  laterally  while  it  is  rapidly  turning  upon  its 
axis.  This  lateral  motion  of  the  hand-piece  will  cause  the  bur " 
to  cut  much  more  rapidly  than  when  held  simply  against  the 
work.  Use  the  smaller  size  first,  and  when  it  has  entered  the 
pit  change  it  for  a  larger,  using  this  in  a  similar  way  and  follow 
this  again  with  a  larger  size.     Then  the  round  bur  should  be 


USE    OF    THE    DENTAL    ENGINE.  35 

laid  aside  and  the  cavity  finished,  if  further  enlargement  is 
required,  with  other  instruments.  There  is  no  other  use  for  a 
round  bur  in  excavating  cavities.  It  should  never  be  used  for 
removing  decayed  dentine.  If  the  pit  cavity  requires  no  fur- 
ther extension  the  round  bur  should  be  followed  by  an  inverted 
cone  that  will  square  out  the  pulpal  or  axial  wall  of  the  cavity 
and  make  the  angles  with  the  surrounding  walls  sharp  and  defi- 
nite. * "  A  cavity  with  rounded  angles  is  the  most  difficult  of  all 
cavity  forms  to  fill  perfectly.  For  other  purposes  in  excavating 
it  is  a  matter  of  choice  in  individual  cases  between  the  use  of  the 
inverted  cone  and  the  fissure  burr.  These  burs  should  be  used 
in  se\eral  positions  which  will  be  pointed  out. 

Cutting  seats  or  steps  for  anchorage  in  mesio  or  disto- 
occlusal  cavities  in  the  bicuspids  and  molars. —  After  the 
mesial  or  distal  cavity  has  been  well  opened  with  cutting  instru- 
ments, and  the  cutting  of  a  step  in  the  occlusal  surface  is 
required,  choose  a  small  inverted  cone  or  fissure  bur,  never  more 
than  one  millimeter  in  diameter,  and  begin  within  the  dentin 
close  against  the  dento-enamel  junction,  causing  the  bur  to 
enter,  and  then  draw  it  to  the  surface  of  the  enamel  ;  engage  it 
again  in  the  same  way  and  repeat  the  motion.  With  this  move- 
ment, using  a  small  bur,  a  groove  is  readily  cut  through  the 
enamel  into  the  center  of  the  occlusal  surface.  In  this  cutting 
the  line  of  the  mesial  (or  distal)  groove  should  be  followed, 
because  this  is  the  weakest  part  of  the  enamel.  If  the  bur 
is  too  large,  it  will  not  cut  so  well.  It  is  only  by  concen- 
trating the  force  on  a  small  bur  that  the  enamel  can 
be  cut  to  any  advantage,  and  even  then  the  cut  should 
be  made  from  within  outward.  After  this  first  cut  has  beea 
made  the  groove  or  channel  formed  should  be  broadened  by 
chipping  away  the  enamel  with  chisels,  or  the  enamel  hatchets, 
and  the  inverted  cone  bur  again  used  to  undermine  the  enamel 
upon  either  side,  which  is  again  chipped  away.  In  this  way  a 
seat  or  occlusal  step  of  any  required  extent  is  readily  formed, 
the  pulpal  wall  of  which  will  have  sharp  and  definite  angles  with 
its  surrounding  walls. 

Grooves  that  need  to  be  cut  out,  merely  for  the  purpose 
of  finding  a  position  for  finishing  the  filling,  i.  e. ,  when  there  is 
solid  dentin  beneat^h,  are  to  be  cut  in  the  same  manner,  with 
the  inverted  cone  or  fissure  bur.      In  none  of  these  cases  should 


36  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

any  attempt  be  made  to  cut  the  enamel  from  without  inward  with 
the  bur.  Cutting  enamel  with  the  bur  dulls  the  blades  very 
quickly.  After  the  bur  has  been  used  for  this  purpose  a  few 
times,  it  should  be  discarded  and  a  new  one  employed.  The 
dull  bur  may  be  sharpened  by  the  instrument  maker. 

In  squaring  out  angles  of  cavities,  the  inverted  cone  bur 
may  often  be  used  to  advantage  in  such  positions  as  are  readily 
accessible,  as  in  occlusal,  labial  and  buccal  cavities.  Usually  this 
is  done  by  flattening  the  pulpal  wall  in  occlusal  cavities,  or  the 
axial  wall  in  buccal  or  labial  cavities.  In  order  to  accomplish 
this  with  the  bur  the  approach  must  be  such  that  the  square  end 
of  the  bur  may  be  placed  in  the  plane  of  the  pulpal  or  axial  wall 
to  be  formed,  or,  in  other  words,  the  axis  of  the  hand-piece 
must  be  at  right  angles  to  the  pulpal  or  axial  wall  to  be  formed. 
Then  the  side  or  periphery  of  the  bur  is  engaged  in  the  deeper 
part  of  the  rounded  pulpal  or  axial  wall,  and  made  to  cut 
toward  one  of  the  surrounding  walls.  This  is  then  repeated  in 
another  direction,  and  the  bur  is  finally  carried  in  a  similar  way 
around  the  whole  circumference  of  the  cavity  in  such  a  way 
that  its  square  end  leaves  the  pulpal  or  axial  wall  flat,  and 
its  line  angles  with  the  surrounding  walls  are  made  sharp  and 
definite. 

The  right-angle  hand-piece  is  often  useful  for  doing  this 
work  in  occlusal  cavities  in  the  lower  second  and  third  molars, 
and  occasionally  in  buccal  cavities  in  these  teeth.  With  it  the 
proper  position  of  the  bur  may  be  obtained  in  these  places  that 
are  not  accessible  to  the  straight  hand-piece.  The  right-angle 
hand-piece,  as  at  present  constructed,  is  an  awkward  instrument, 
and  it  should  be  used  only  in  well  chosen  positions,  inaccessible 
to  the  straight  hand-piece.^  In  most  cases  this  squaring  out  of 
the  pulpal  or  axial  walls  to  definite  angles  with  the  surrounding 
walls  is  done  just  as  easily  and  quickly  with  the  hoes  12-5-6, 
1 2-5- 1 2,  or  the  8-3-6  or  12,  used  with  a  scraping  motion. 
These  instruments  will  reach  any  of  these  positions  if  the  sur- 
rounding walls  have  been  properly  formed  previous  to  their  use. 

In  making  extensions  for  prevention  in  any  of  the  axial 
surface  cavities  the  small  inverted  cone  burs  may  be  used  to 
advantage.      If,   in  excavating  proximate  cavities,  we  find  that 


*It  is  now  expected  that  a  contra-angled  hand-piece  that  will  be  much  more  useful, 
will  be  on  the  market  soon. 


USE    OF    THE    DENTAL    ENGINE.  6i 

after  cutting  the  gingival  wall  to  sound  dentin  it  is  desirable  to 
extend  the  cavity  further  to  the  gingival,  place  the  end  of  an 
inverted  cone  bur,  five  to  eight-tenths  of  a  millimeter  in  diameter, 
against  the  gingival  wall  upon  the  dentin,  close  against  the 
dento-enamel  junction,  and  incline  the  hand-piece  just  enough 
to  cause  the  periphery  of  the  bur  to  cut,  and  press  it  toward  and 
into  the  bucco-gingival  angle,  then  incline  the  hand-piece  in  the 
opposite  direction  and  press  the  bur  in  the  linguo-gingival  angle. 
Now,  by  repetitions  of  these  movements  cut  as  deeply  to  the 
gingival  as  may  be  required,  keeping  close  against  the  dento- 
enamel  junction.  This  undermines  the  enamel,  which  is  now 
easily  removed  with  the  enamel  hatchets.  In  extending  to  the 
buccal  or  to  the  lingual  the  enamel  hatchets  generally  serve  best, 
but  occasionally  the  operation  is  facilitated  by  starting  a  small 
inverted  cone  bur  in  the  axio-bucco-gingival  angle  and  drawing 
it  to  the  occlusal,  cutting  away  the  dentin  of  the  buccal  wall 
just  beneath  the  enamel,  which  is  then  removed  with  the  enamel 
hatchet.     The  same  operation  is  repeated  upon  the  lingual  wall. 

In  this  extension  it  is  important  that  the  bur  be  kept  close 
against  the  enamel  so  that  it  shall  not  cut  into  the  tooth  so 
deeply  as  to  endanger  the  pulp.  There  should  be  no  attempt  to 
cut  the  enamel  with  the  bur,  for  the  reason,  first,  that  it  is  not 
easily  done,  and  second,  because  it  ruins  the  bur.  Whenever  it 
is  regarded  as  important  that  enamel  should  be  cut  with  a  bur 
one  must  expect  that  the  bur  will  be  ruined  in  the  operation.  , 
That  is  to  say,  the  blades  will  be  so  dulled  that  it  will  be  unfit 
for  further  use,  and  a  new  bur  must  be  provided  for  the  next 
operation.  A  good  bur  will  cut  dentin,  however,  for  many 
operations. 

In  making  starting  points  for  packing  gold  the  smaller 
inverted  cone  bur  is  especially  useful.  In  mesial  and  distal 
cavities  in  nearly  all  positions,  starling  points  in  the  axio-linguo- 
gingival  angle  and  the  axio-gingivo-buccal  (or  laljial;  angle  are 
important  conveniences.  They  are  best  made  by  placing  the 
end  of  an  inverted  cone  bur  in  the  angles  named,  and  by  a 
slight  swaying  of  the  hand-piece  cause  the  bur  to  enter  just  a 
little,  then  draw  the  bur  toward  the  occlusal  (or  incisal  if  in 
incisor  cavities),  a  short  distance,  making  a  slight  groove  lead- 
ing away  from  the  pit  first  formed  to  give  strength  to  the  gold 
when  placed.      The  pit  itself  shtjuld   not   be   directed   into   the 


38  THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

gingival  wall,  or  only  slightly,  but  to  the  lingual  or  buccal 
(labial  in  the  incisors  and  cuspids),  and  the  groove  should  be 
close  against  the  axio-buccal  or  axio-lingual  line  angle.  In  this 
method  of  cutting  these  starting  points  the  square  end  of  the  bur 
gives  a  square  floor  to  the  pit  at  the  point  where  the  first  piece 
of  gold  is  placed,  which  prevents  any  tendency  of  the  gold  to 
roll  from  side  to  side  in  the  first  efforts  to  condense  it,  so  that  a 
very  shallow  pit,  a  mere  corner  or  sharp  angle,  so  to  speak,  is 
all  that  is  necessary.  It  should  be  remembered  always  that 
these  convenience  points  are  not  anchorage  points  for  the  filling, 
but  are  simply  starting  points  for  the  temporary  anchorage  of  the 
first  pieces  of  gold. 

The  use  of  drills  should  be  confined  to  certain  especial 
purposes.  These  should  be  used  when  for  any  reason  it  becomes 
necessary  to  cut  into  the  pulp-chamber  of  a  sound  tooth,  or  one 
that  has  already  been  filled.  This  necessity  occurs  frequently 
because  of  hyperaemia  of,  or  death  of,  the  pulp  after  a  filling  has 
been  made,  or  from  death  of  the  pulp  from  a  blow  or  some 
unknown  cause.  In  these  cases  it  is  often  necessary  to  cut  from 
the  surface  of  the  tooth  to  the  pulp-chamber,  either  through  a 
filling  or  through  the  enamel  and  dentine.  The  bur  is  not  suit- 
able for  this  work.  The  flat  drill,  bi-beveled  to  a  point,  is  the 
proper  instrument,  or  the  drill  followed  by  a  round  bur  to  enlarge 
the  opening.  In  doing  this  where  considerable  tissue  is  to  be 
cut  through,  it  is  best  to  use  a  small  drill  first,  and  when  this  has 
penetrated  some  distance,  enlarge  the  opening  with  a  larger  drill 
or  a  round  bur,  then  penetrate  further  with  the  small  drill  and 
again  enlarge.  Proceed  in  this  way  until  the  pulp-chamber  is 
reached.  In  the  attempt  to  drill  deeply  with  a  small  flat  drill  the 
instrument  does  not  clear  itself  of  chips  readily  and  is  apt  to 
heat  ;  also,  it  is  likely  to  be  broken  by  any  movement  of  the 
patient. 

The  drill  is  also  the  best  instrument  for  enlarging  root-canals 
for  setting  posts  or  pins  for  artificial  crowns.  It  will  be  seen  that 
these  uses  of  the  drill  are  aside  from  cavity  excavation. 

The  Use  of  Water. 

The  use  made  of  water  in  operative  dentistry  is  very  impor- 
tant. Every  dental  office  should  have  a  liberal  supply  of  both 
warm  and  cold  water.     The  use  of  water  for  the  hands  of  the 


THE    USE    OF    A\'aTER.  39 

operator  is  in  itself  important,  and  the  wash  basin,  while  not 
necessarily  before  or  about  the  operating  chair,  should  be  conve- 
nient, and  in  such  position  that  the  patient  may  at  least  know 
when  the  operator  washes  his  hands.  Cleanliness  and  neatness 
are  important  in  gaining  and  in  holding  a  practice. 

Water  should  be  constantly  ready  for  use  at  the  operating 
chair  for  washing  the  teeth  and  gums  of  patients.  For  use  in 
the  mouth  water  should  genei'ally  be  heated  to  about  105  degrees 
Fahrenheit,  or  just  a  little  warmer  than  blood  temperature.  In 
the  large  majority  of  cases  this  temperature  will  be  found  most 
grateful  to  patients.  If,  however,  cases  occur,  as  they  will,  in 
which  some  of  the  teeth  are  very  sensitive  to  thermal  changes, 
the  temperature  of  105  degrees  will  cause  considerable  pain,  and 
in  such  cases  the  temperature  should  be  carefully  reduced  to  gS}4 
degrees,  or  blood  temperature. 

The  uses  of  water  at  the  operating  chair  are  : 

For  cleaning  the  teeth  preparatory  to  operating. 

For  keeping  the  teeth  and  mouth  free  from  blood  and  debris 
while  removing  calculus,  or  in  doing  any  operations  upon  dis- 
eased gums,  or  while  treating  diseases  of  the  peridental  mem- 
branes. 

For  washing  cavities  during  any  portion  of  the  work  of 
excavating  that  may  be  done  before  placing  the  rubber  dam. 

For  cleaning  the  necks  of  the  teeth  before  applying  the  rub- 
ber dam. 

For  treating  the  gums  after  removing  the  rubber  dam. 

For  removing  debris  and  polishing  powders  during  any  por- 
tion of  the  polishing  of  fillings  that  may  be  done  without  the 
rubber  dam. 

P'or  any  and  all  of  these  uses  a  good  rubber-bulb  water 
syringe  which  will  hold  a  little  more  than  a  gill  is  necessary.  A 
little  bit  of  a  water  syringe  is  a  nuisance.  A  syringe  should  be 
used  with  which  the  mouth  can  be  flooded  with  water,  or  a  strong 
continuous  stream  thrown  for  several  seconds. 

For  cleaning  the  teeth  preparatory  to  operating,  warm 
water  should  be  used  in  almost  every  case,  even  though  the  teeth 
are  apparendy  in  a  cleanly  condition.  In  the  best  of  conditions 
there  is  usually  more  or  less  gummy  material  containing  many 
micro-organisms  about  the  necks  of  the  teeth,  or  about  cavities, 
especially  proximal,  buccal  and  labial  cavities,  which  should  be 


40  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

loosened  up  with  scalers  and  removed  with  a  strong  stream  of 
water.  In  very  many  cases  the  teeth  should  be  cleaned  with  a 
rubber  disk  and  powdered  stone  and  washed  clean  with  a  jet  of 
water  before  anything  is  done  toward  excavating  cavities.  In 
all  cases  the  field  of  operation  should  be  made  clean  as  the  first 
procedure. 

The  use  of  water  while  removing  calculus  is  impera- 
tive. The  field  of  operation  requires  to  be  repeatedly  washed 
with  strong  jets  of  water,  in  order  to  do  both  operator  and 
patient  justice.  This  is  necessary  in  order  to  remove  blood  and 
debris  that  the  next  step  of  the  operation  may  be  seen.  It  is 
necessary  to  impart  a  sense  of  cleanliness  and  comfort  to  the 
patient.  It  is  necessary  to  the  removal  of  particles  of  loosened 
calculus  from  about  the  necks  of  teeth. 

In  excavating  cavities  water  should  be  used  freely  in 
any  portion  of  the  operation  that  is  done  before  placing  the  rub- 
ber dam.  In  many  cases  it  is  desirable  to  open  cavities  and  do 
the  rougher  parts  of  the  excavating  before  the  dam  is  applied. 
During  such  part  of  the  operation  as  may  be  done  without  the 
rubber  dam  the  cavity  should  be  frequently  washed  with  strong 
jets  of  water  of  the  proper  temperature  for  the  purpose  of 
removing  all  debris  from  the  cavity  and  from  the  mouth  of  the 
patient. 

Before  placing  the  rubber  dam  water  should  be  used 
to  free  the  necks  of  the  teeth  from  micro-organisms,  even 
in  the  most  cleanly  mouths.  A  thin  scaler  should  be  passed 
around  all  of  the  surfaces,  loosening  up  any  gummy  substance 
adhering  to  them,  and  this  should  be  washed  away  with  a  strong 
jet  of  warm  water.  If  the  case  is  not  especially  cleanly  there  is 
greater  necessity  for  this  proceeding,  provided,  of  course,  that 
this  has  not  been  done  preparatory  to  '  some  previous  operation 
at  the  same  sitting. 

The  object  of  this  care  is  especially  to  prevent  pushing  a 
mass  of  micro-organisms  and  debris  under  the  free  margin  of 
the  gum  by  the  rubber  and  the  ligature.  Often  the  gums  are 
more  or  less  bruised  by  this  procedure,  and  if  at  the  same  time 
a  mass  of  debris  containing  many  active  micro-organisms  is 
crowded  into  the  soft  tissue  and  held  there  for  a  considerable 
time,  the  micro-organisms  will  take  hold  of  this  injured  tissue 
and  cause  very  inconvenient  soreness,    or  actual  suppuration. 


THE    RUBBER    DAM. 


41 


Many  incurable  cases  of  phagedenic  pericementitis  are  started 

in  this  way. 

After  removing  the  rubber  dam  the  gums  should  be 
treated  with  a  thorough  douching  with  w^arm  water 
while  kneading  them  thoroughly  with  the  fingers  of  the 
other  hand.  This  is  especially  important  to  the  comfort  of  the 
patient.  The  rubber  dam  has  been  in  place  for  a  considerable 
time,  perhaps  for  one,  two  or  three  hours,  and  during  this  tune 
the  free  margins  of  the  gums  have  been  tightly  compressed  by 
the  rubber  and  the  ligatures  or  other  appliances  for  securing  it 
in  place.  The  circulation  of  the  blood  through  this  part  has 
been  stopped.  The  douching,  together  with  the  kneading, 
causes  the  blood  to  return  to  these  tissues,  starts  it  into  active 
circulation  again,  and  removes  any  poisonous  material  that  may 
have  been  forced  into  the  gingival  space  by  the  rubber.  It 
imparts  a  feeling  of  comfort  to  the  parts  and  causes  at  once  the 
most  complete  feeling  of  rest  from  the  operation  that  it  is  possible 
for  the  operator  to  give. 

The  washing  away  of  powdered  stone  and  debris 
during  and  after  polishing  fillings  should  be  thorough  and  com- 
plete, and  the  patient  dismissed  with  a  clean  mouth,  free  from 
all  grit  and  dirt  of  any  sort  that  has  been  used.  Always  look 
particularly  to  the  comfort  of  your  patients  and  they  will  reward 
you  for  your  care. 

The   Rubber   Dam. 

The  objects  to  be  attained  by  the  use  of  the  rubber  dam  are  : 
to  keep  cavities  dry  and  clean  while  excavating  and  while  mak- 
ing fillings ;  to  better  expose  and  bring  the  parts  into  view  ;  and 
to  prevent  ingress  of  saliva  and  micro-organisms  during  the 
treatment  and  filling  of  root  canals. 

In  using  the  rubber  dam  it  should  be  remembered  that  it  is 
disagreeable,  sometimes  painfully  so,  to  patients,  and,  therefore, 
its  use  should  be  restricted  to  the  actual  necessities  of  the  case 
in  hand,  and  the  time  it  remains  in  place  should  be  made  as  short 
as  practicable. 

When  the  cavity  to  be  prepared  is  in  sufficiently  plain  view, 
and  the  conditions  are  such  that  the  saliva  will  not  obscure  the 
seat  of  operation,  the  ru'ober  dam  should  not  be  placed  until  the 
rougher  parts  of  the  excavating  is  done.      In  excavating  cavities 


42 


THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 


in  the  upper  teeth  a  considerable  portion  of  the  work  may  often 
be  done  before  applying  the  rubber  dam,  but  it  should  always  be 
in  place  before  the  excavation  is  finished,  and  remain  until  after 
the  filling  is  completed.  The  rule  should  be  that  the  walls  of  a 
cavity  should  never  become  damp  after  the  last  of  the  cutting  is 
done  in  their  preparation. 

If,  however,  it  appears  from  the  position  of  the  tooth,  and 
the  conditions  present,  that  the  field  of  operation  will  be  contin- 
ually overflowed  by  saliva,  or  that  the  case  is  particularly  diffi- 
cult to  see,  the  rubber  dam  should  be  placed  before  beginning 
the  operation.  In  proximate  cavities  it  is  generally  best  to  open 
the  cavity  by  cutting  away  the  overhanging  enamel,  and  to  deter- 
mine the  position  of  the  gingival  wall  of  the  prepared  cavity  with 
some  degree  of  certainty  before  applying  the  rubber  dam.  This 
will  usually  facilitate  the'  application  of  it,  and  in  obtaining  its 
proper  position  in  relation  to  the  gingival  wall. 

Preparations   for   Applying  the   Rubber   Dam. 

The  rubber  dam  should  be  tough  and  very  elastic.  Gener- 
ally a  medium  thickness  should  be  employed.  It  should  be  cut 
in  pieces  about  six  inches  square.  Before  making  any  effort  to 
apply  it,  the  teeth  should  be  well  cleaned  and  douched  with  a 
stream  of  warm  water  from  the  syringe  to  free  them  from  gummy 
material,  and  from  collections  of  micro-organisms  that  would 
otherwise  be  forced  under  the  free  margins  of  the  gums,  or  even 
into  the  soft  tissues,  by  the  ligatures  or  clamps.  The  interproxi- 
mate  space  should  be  cleaned  by  use  of  the  ligature  passed 
between  the  contact  points.  In  doing  this  the  difficulties  to  be 
met  with  in  passing  the  rubber  between  the  teeth  will  be  deter- 
mined. The  position  and  size  of  the  holes  in  the  dam  should 
next  be  determined,  together  with  the  number  of  teeth  to  be 
included.  Not  less  than  three,  generally  four  or  five  teethi 
should  be  included.  If  a  front  tooth  is  to  be  filled,  include  four 
or  more,  always  one  or  two  on  either  side  of  the  tooth  to  be 
operated  upon  ;  if  a  bicuspid  or  first  molar,  include  one  tooth 
to  the  distal,  and  at  least  two  to  the  mesial  ;  if  the  second  molar 
and  the  cavity  involves  the  distal  surface,  include  the  third 
molar  ;  if  the  cavity  does  not  involve  the  distal  surface,  the 
inconvenience  of  placing  the  rubber  upon  the  third  molar  will 
be  greater  in  many  cases  than  to  do  the  operation  with  a  clamp 


THE    RUBBER    DAM.  4?j 

on  the  second  molar.      In   all  cases   there  should  be  as  clear  a 
field  and  as  much  room  for  operating  as  practicable. 

The  holes  in  the  rubber  should  be  placed  in  such  position 
that  when  applied  it  will  cover  the  upper  lip,  lower  lip  and  chin, 
but  should  not  cover  the  nostrils  of  the  patient  and  interfere 
with  the  breathing.  The  distance  between  the  holes  is  an 
important  consideration.  They  should  always  be  as  far  apart  as 
the  mesio-distal  breadth  of  the  teeth  to  be  included.  In  case  of 
bicuspids  and  lower  incisors  that  have  thin  necks  mesio-distally, 
the  distance  should  be  a  little  greater.  This  is  necessary  to 
prevent  the  septum  of  rubber  between  the  teeth  from  stretching 
into  so  narrow  a  band  that  it  will  fail  to  hug  so  closely  to  the 
necks  of  the  teeth  as  to  exclude  moisture. 

Rubber  Dam  Grasps. 

The  particular  manner  of  grasping  the  rubber  dam  when 
about  to  apply  it  is  very  important,  and  should  be  studied  with 
much  care  in  the  beginning  of  the  student's  experience.  Cer- 
tain ways  of  grasping  the  rubber  dam  are  particularly  suited  to 
the  application  of  it  in  certain  positions  in  the  mouth,  or  to  cer- 
tain teeth ;  also  to  certain  positions  of  the  operator  when  apply- 
ing it.  If  these  are  well  learned  in  the  beginning  it  will  save 
much  time,  and  much  of  the  difficulty  in  attaining  facility  in 
this  work. 

In  considering  these  grasps  the  side  of  the  rubber  which, 
when  applied,  will  be  next  the  gingivre  is  called  the  gingival 
side,  and  that  which  will  be  toward  the  occlusal  surfaces  of  the 
teeth  is  called  the  occlusal  side. 

The  first  grasp  is  used  when  tlie  dam  is  to  be  applied  to 
the  upper  front  teeth.  Grasp  the  rubber  between  the  thumb 
and  finger  of  each  hand,  with  the  ends  of  the  thumbs  on  the 
occlusal  side  of  the  rubber  and  their  ends  touching  together 
immediately  over  the  hole  to  be  first  used,  and  the  finger-ends 
midway  the  balls  of  the  thumbs.  .Stretch  the  rubber  a  litde 
with  the  thumbs  still  touching  end  to  end.  Then  stretch  the 
rubber  a  little  more,  and,  standing  to  the  right  and  in  front  of 
the  patient,  pass  the  hole  o\  er  the  tooth;  the  right  thumb  on 
the  lingual  and  the  left  on  the  labial  side.  In  doing  this,  first 
place  the  free  edge  of  the  rubber  at  one  side  of  the  hole  between 
the   teeth,  and  with  a  slight   sawing   motion   force  it   past   the 


44  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

contact  on  that  side.  Then  stretch  it  over  the  tooth  and  force  it 
past  the  contact  on  its  other  side  in  a  similar  way.  Now  carry- 
each  of  the  thumbs  against  the  gingivae.  At  this  point  hold  the 
thumbs  in  position  for  an  instant,  release  the  hold  of  the  rubber 
with  the  fingers  and  allow  it  to  draw  around  the  neck  of  the 
tooth  before  loosing  the  pressure  of  the  thumbs.  Generally  the 
rubber  will  be  felt  to  draw  around  the  thumbs,  and  then  they 
should  be  given  a  slight  shaking  motion  which  will  allow  the 
rubber  to  draw  around  the  tooth  before  releasing  the  pressure, 
and  removing  them.  When  the  rubber  is  applied  in  this  way 
it  will  generally  be  found  to  cling  to  the  neck  of  the  tooth  and 
have  its  cut  edge  turned  under  the  gingivae.  Repeat  this 
motion  with  each  hole  in  the  rubber,  grasping  it  anew,  and  in 
the  same  manner  for  each,  and  pass  it  over  the  appropriate 
tooth  with  a  similar  motion.  This  grasp  and  these  motions  will 
answer  for  all  of  the  upper  teeth  as  far  back  as  the  first  molars. 
When  applying  it  with  this  grasp  to  the  teeth  of  the  left  side, 
the  face  of  the  patient  should  be  turned  strongly  to  the  right;  or 
the  operator  should  pass  to  the  left  side  of  the  patient. 

The  second  grasp  is  a  modification  of  the  first,  which 
allows  the  left  hand  of  the  operator  to  be  passed  around  the 
head  of  the  patient  when  standing  to  the  right  of,  and  partially 
behind,  the  chair.  This  will  generally  be  found  more  conven- 
ient for  the  upper  teeth  of  the  left  side  as  far  as  the  bicuspids. 
In  this  the  rubber  is  grasped  with  the  right  hand  in  the  same 
way  as  before,  but  with  the  left  hand  the  grasp  is  inverted  so 
that  the  forefinger  takes  the  place  of  the  thumb,  or  is  on  the 
occlusal  side  of  the  rubber,  with  the  thumb  about  oj)posite  the 
first  joint  of  the  finger.  In  applying  the  dam  with  this  grasp 
the  thumb  of  the  right  hand  is  placed  on  the  li;igual  side  of  the 
tooth  and  the  forefinger  of  the  left  on  the  labial,  or  buccal  side. 
Otherwise  than  this  change  of  positions  the  motions  with  which 
the  rubber  is  placed  are  the  same  as  with  the  first  grasp.  This 
grasp  is  also  suitable  for  the  application  of  the  rubber  to  the 
lower  teeth  of  the  right  side  as  far  back  as  the  second  bicuspid, 
the  operator  standing  to  the  right  and  partially  behind  the 
patient.  In  this  position  the  forefinger  of  the  left  hand  will  be 
placed  to  the  lingual  of  the  tooth  and  the  thumb  of  the  right 
hand  to  the  buccal. 

The  third  grasp  is  a  modification  of  the  second,  in  which 


THE    RUBBER    DAM.  45 

the  two  hands  are  simply  inverted,  so  that  the  thumb  of  the  left 
is  on  the  occlusal  side  of  the  rubber  and  the  thumb  of  the  right 
is  on  the  lingual  side.  In  e\ery  other  way  the  grasp  is  the 
same.  This  is  suited  to  placing  the  rubber  on  the  lower  teeth 
of  the  left  side  of  the  mouth  as  far  back  as  the  second  bicuspid; 
the  operator  standing  on  the  right  and  passing  the  left  hand 
around  the  head. 

The  fourth  grasp  is  a  complete  inversion  of  the  first.  In 
this  the  thumbs  are  both  placed  on  the  gingival  side  of  the  rub- 
ber, and  both  forefingers  on  the  occlusal  side.  The  rubber  is 
grasped  with  the  thumbs  opposite  the  first  joint  of  the  forefin- 
gers, or  thereabouts.  The  ends  of  the  forefingers  come  together 
over  the  hole  to  be  used,  not  directly  end  to  end,  but  in  the 
form  of  a  letter  V,  the  finger-ends  forming  the  angle.  The 
rubber  is  now  stretched  so  as  to  open  the  hole  slightly  while  the 
finger-ends  are  close  against  its  margins.  Then  it  is  carried 
over  the  tooth,  stretching  the  rubber  sufficiently  by  spreading 
the  fingers  apart,  made  to  pass  the  contact  points  between  the 
teeth  one  after  the  other  by  a  slight  sawing  motion,  and  the 
finger-ends  carried  hard  against  the  gingivae,  one  on  the  buccal 
side  and  one  on  the  lingual  side  of  the  tooth.  Then  the  grasp 
of  the  thumbs  is  released  while  maintaining  the  position  of  the 
fingers  and  the  rubber  allowed  to  draw  around  the  tooth.  If 
the  rubber  is  felt  to  close  on  the  finger-ends,  which  it  will  often 
do,  and  fail  to  close  on  the  tooth,  make  a  slight  oscillating 
motion  of  the  fingers  which  will  allow  it  to  slip  past  them  and 
hug  to  the  tooth  before  removing  the  fingers.  The  rubber  is 
now  gras])ed  anew  and  in  the  same  way  to  be  passed  over  the 
next  tooth,  being  careful  to  place  the  finger-ends  very  close  on 
either  side  of  the  hole  to  be  used  in  each  instance. 

This  grasp  is  i)articularly  suited  to  the  upper  bicuspids  and 
first  molars,  the  operator  standing  partially  behind  and  above 
the  patient.  For  this  the  head  of  the  patient  should  be  thrown 
well  backward.  Often,  also,  this  grasp  w  ill  be  very  convenient 
for  placing  the  rubber  on  the  lower  bicuspids  and  first  molars, 
the  operator  standing  to  the  right  and  in  front  of  the  patient. 
For  this  position  the  head  of  the  patient  shoukl  be  ujiright. 

The  fifth  grasp  is  used  especially  for  placing  the  dam  on 
the  second  and  third  molars,  or  where  it  is  necessary  to  reach 
far  back  into  the  mouth.      In  this  the  dam  is  first  taken  between 


46  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

the  first  and  second  fingers  of  each  hand  with  the  forefingers  and 
thumbs  on  the  occlusal  side.  Then  the  second,  third  and  fourth 
fingers  are  closed,  or  nearly  closed,  and  the  dam  grasped  be- 
tween the  thumbs  and  second  fingers  with  the  thumbs  placed 
opposite  the  second  joint  of  the  fingers,  or  between  the  first  and 
second  joints.  With  this  grasp  stretch  the  dam  a  little  and 
engage  the  two  forefingers  in  it  close  on  either  side  of  the  hole 
to  be  used  and  with  them  stretch  the  hole  open.  It  is  generally 
necessary  that  the  hole  be  opened.sufificiently  wide  so  that  the 
tooth  to  which  it  is  to  be  applied  can  be  seen  through  it.  Then 
carry  it  back  into  the  mouth  and  pass  it  over  the  tooth  with  the 
forefingers,  the  one  on  the  buccal,  the  other  on  the  lingual,  and 
engage  one  edge  of  the  hole  between  the  teeth,  preferably  the 
mesial  first,  and  cause  it  to  pass  the  contact  by  a  sawing  motion. 
When  this  has  passed  into  the  interproximate  space  throw  the 
rubber  over  the  distal  surface,  and  if  it  is  a  second  molar  pass 
the  contact  in  a  similar  way.  Then  carry  each  of  the  finger- 
ends  hard  against  the  gums  on  either  side,  buccal  and  lingual, 
of  the  tooth  and  holding  them  firmly  in  position  release  the  dam 
with  the  thumbs  and  second  fingers.  The  dam  will  now  draw 
around  the  tooth,  or  else  it  will  be  felt  drawing  on  the  ends  of 
the  forefingers.  In  the  latter  case  a  little  motion  of  the  ends  of 
the  fingers  will  allow  the  dam  to  slide  by  them  and  close  firmly 
around  the  tooth.  Then,  and  not  till  then,  the  fingers  may  be 
removed.  The  dam  may  now  be  grasped  again  in  the  same  way 
and  the  forefingers  engaged  on  either  side  of  the  next  hole  to  be 
used  and  it  brought  over  the  next  tooth,  whether  to  the  mesial 
or  distal,  in  a  similar  manner.  Notice  particularly  that  the 
grasp  on  the  rubber  is  to  be  released  entirely  at  the  end  of  its 
application  to  each  particular  tooth  and  grasped  anew  for  the 
next. 

It  is  just  as  important  to  know  how  to  remove  the  fingers 
from  the  rubber  without  pulling  the  rubber  away  with  them  after  it 
has  been  placed  on  the  tooth  as  it  is  to  place  the  rubber  over 
the  tooth  ;  and  I  wish  to  emphasize  the  necessity  of  noting  very 
carefully  the  manner  of  doing  this,  and  draw  attention  strongly 
to  the  fact  that  the  dam  should  be  allowed  to  fully  close  around 
the  tooth  while  the  fingers  are  still  pressed  against  the  gums  on 
its  buccal  and  lingual  sides.  This  applies  to  all  grasps  whatso- 
ever that  may  be  used  in  adjusting  the  rubber  dam. 


THE    RUBBER    DAM.  47 

In  using  the  fifth  grasp,  the  operator  can  use  the  full  length 
of  the  forefingers  for  reaching  back  into  the  mouth  and  yet  have 
full  command  of  the  rubber  and  readily  place  it  on  any  tooth 
where  the  contacts  can  be  passed  with  a  sawing  motion  of  the 
fingers  ;  and  in  ordinary  cases  it  will  hold  without  the  aid  of  a 
ligature  while  passing  it  over  other  teeth.  Of  course,  there  are 
many  molar  teeth  around  which  the  gums  are  so  high  that  the 
rubber  can  not  be  passed  far  enough  onto  the  crown  in  this  way 
for  it  to  hold.  There  are  also  a  good  many  tooth  crowns  so 
rounded  that  the  dam  must  be  forced  actually  to  the  gingival 
line  and  tied  down  with  a  ligature  or  held  by  a  clamp  before  it 
can  be  induced  to  remain  in  place.  With  these  grasps,  how- 
ever, everything  can  be  done  that  it  is  possible  to  do  with  the 
unaided  fingers. 

The  Use  of  Ligatures  in  Adjusting  the  Rubber  Dam. 

There  are  many  cases  in  which  the  rubber  can  not  be  forced 
between  the  contact  points  of  adjoining  teeth  with  the  unaided 
fingers,  and  then  it  must  be  forced  with  the  ligature.  This  is 
best  done  by  an  assistant.  However,  by  careful  practice  one 
may  learn  to  do  it  successfully  alone.  The  ligature  may  be  used 
with  any  of  the  five  grasps.  To  accomplish  this,  wrap  the  end 
of  the  ligature  on  the  little  finger  of  the  left  hand  and  catch  a 
part  of  its  length  in  the  same  grasp  with  the  rubber  in  the  thumb 
and  finger  of  the  right  hand,  leaving  just  sufficient  length  ■ 
between  so  that  the  ligature  may  be  tightly  drawn  by  a  move- 
ment of  the  little  finger  on  which  it  is  wrapped.  Bring  this 
ligature  over  the  contact  to  be  forced  beside  the  finger,  or  the 
thumb,  of  the  left  hand  at  the  same  time  that  the  rubber  is 
stretched  over  the  tooth.  Then,  by  drawing  with  the  little 
finger  of  the  left  hand  and  by  the  grasp  with  the  right,  the 
ligature  is  forced  through,  carrying  the  rubber  before  it.  To 
get  just  the  right  length  and  adjustment  of  the  ligature  generally 
requires  a  little  maneuvering  in  each  individual  case.  The 
observant  operator  will  see  his  way  clearer  and  be  better  able  to 
avoid  difficulties  with  each  failure. 

In  cases  in  which  considerable  force  is  recjuired  to  drive  the 
rubber  past  the  contact  the  grasp  with  the  fingers  is  often  insuffi- 
cient. The  ligature  will  slip  in  the  fingers  and  the  rubber  will  be 
stretched  •  too  much,  and  a  general  derangement  of  the  position 


48  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

will  result.  In  this  case  it  will  be  necessary  to  arrange  to  use 
greater  force.  To  do  this,  wrap  the  ligature  on  the  little  finger 
of  each  hand,  noting  carefully  that  the  length  between  the  fingers 
is  just  right.  It  will  often  be  necessary  to  try  this  length  a 
number  of  times  before  getting  it  to  exactly  suit  the  particular 
case.  Then  bring  the  ligature  over  the  contact  and  under  one 
of  the  fingers  or  thumb  with  which  the  rubber  is  forced  down, 
and  stretch  down  the  rubber  into  the  embrasure  as  far  as  possible; 
then  draw  the  ligature  with  the  little  fingers  so  as  to  tighten  it 
on  the  rubber  to  hold  it,  and  work  the  finger  on  the  opposite 
side  of  the  tooth  onto  the  ligature,  so  that  it  may  be  forced  on 
both  sides  of  the  tooth  at  the  same  time.  The  accomplishment 
of  this  last  movement  is  the  most  difficult  point,  but  it  can 
generally  be  done  after  a  few  efforts,  and  then  the  operator  has 
command  of  the  situation.  The  rubber  can  be  forced  into  the 
contact  with  all  of  the  power  of  the  fingers.  After  forcing  the 
first  contact  the  grasp  of  the  rubber  must  generally  be  released,  a 
second  ligature  wrapped  on  the  fingers,  the  rubber  grasped  anew, 
and  the  second  contact  forced  in  the  same  way.  This  may  now 
be  continued  until  the  rubber  has  been  placed  on  a  sufficient 
number  of  teeth.  Generally,  when  the  rubber  has  been  forced, 
past  one  close  contact  this  holds  the  rubber  as  a  starting  point, 
and  the  rest  is  much  easier  of  accomplishment.  Very  much  of 
the  difficulties  of  adjusting  the  rubber  is  relieved  by  having  an 
assistant  pass  a  ligature,  or  set  a  clamp  in  position  in  these 
difficult  cases. 

Another  method  of  avoiding  the  most  serious  difficulty  in 
passing  ligatures  to  force  the  rubber  between  teeth  far  back  in  the 
mouth  is  to  set  a  special  clamp  on  the  tooth  first,  and  then  throw 
the  rubber  over  the  bows  of  the  clamp.  For  this  purpose  the 
fifth  grasp  should  be  used,  and  the  hole  in  the  rubber  should  be 
a  little  larger  than  usual.  The  ends  of  the  forefingers  should  be 
placed  fully  to  the  distal  side  of  the  hole,  or  so  that  its  distal 
edge  is  fully  between  the  finger-ends  and  upon  their  planter 
surfaces.  Then  it  must  be  so  stretched  that  the  distal  edge  of 
the  hole  may  be  passed  over  the  distal  edge  of  the  bow  of  the 
clamp,  starting  it  first  over  its  lingual  portion  and  sweeping  it 
around  over  the  buccal  portion.  Then  release  the  rubber,  and 
by  a  little  careful  motion  of  the  fingers  it  is  allowed  to  close 
around  the  tooth  under  the  clamp.     This  is  generally  done  easily 


THE    RUBBER    DAM.  49 

and  quickly  when  the  particular  relation  of  the  fingers  to  the  hole 
in  the  dam  is  appreciated.  After  this  starting  point  has  been 
secured  it  is  not  so  very  difficult  to  secure  the  rubber  over  the 
teeth  mesial  to  it. 

Passing  the  contact  with  ligatures  should  be  done  with  much 
care,  for  if  it  is  allowed  to  snap  onto  the  gums  it  will  often  induce 
considerable  pain  and  do  the  patient  a  real  injury  by  cutting  into 
the  tissues.  To  avoid  this,  always  catch  the  ligature  very  close 
to  the  tooth  on  both  the  buccal  and  lingual  sides.  This  will  pre- 
vent that  forcible  snap  onto  the  sensitive  tissues  that  is  sure  to 
occur  if  this  precaution  is  not  observed. 

In  manv  cases  a  ligature  must  be  tied  over  the  rubber  to  hold 
it  in  place,  or  to  force  the  gums  sufficiently  to  the  gingival  to 
expose  the  gingival  margin  of  the  cavity.  In  doing  this  the  lig- 
ature should  be  carefully  forced  close  to  the  gingival  line  and 
tightly  drawn  with  a  surgeon's  knot.  Generally  it  is  not  neces- 
sary to  tie  ligatures  on  every  tooth  over  which  the  dam  is  placed. 
Often  when  ligatures  seem  necessary,  if  the  rubber  is  just  drawn 
well  down  the  ligature  may  be  at  once  removed  and  the  rubber 
will  remain  in  position.  Ligatures  are  often  painful  and  when 
the  results  can  be  well  accomplished  without  them  they  should 
not  be  used. 

Often  there  will  be  difficulty  in  adjusting  the  ligature  to  the 
lingual  side  of  the  incisors  with  the  unaided  fingers.  The  shape 
of  the  lingual  surface  causes  it  to  slip  off.  In  these  cases  the 
ligature  should  be  thrown  loosely  around  the  tooth  and  the  first 
half  of  the  knot  formed,  but  before  it  is  drawn  up  the  flat-curved 
burnisher  should  be  passed  to  the  lingual  of  the  tooth  inside  the 
loop  of  the  ligature,  and  carried  to  the  gingival  line  and  so 
inclined  that  when  the  ligature  is  drawn  with  the  other  hand  it 
will  be  guided  to  the  right  position.  Then  the  burnisher  may  be 
removed  and  the  knot  closed.  This  burnisher  is  useful  in  many 
positions  as  an  aid  in  the  adjustment  of  ligatures. 

In  tying  ligatures  about  the  teeth,  the  first  half  of  a  surgeon's 
knot  should  first  be  formed  and  tightly  drawn.  In  doing  this 
the  ligature  should  be  grasped  as  close  to  the  knot  as  practicable, 
and  held  close  against  the  teeth,  both  to  the  mesial  and  to  the 
distal.  If  the  ligature  is  over  the  biduspids  or  molars  catch  the 
distal  end  of  it  over  the  end  of  the  forefinger  of  one  hand  and 
force  it  to  the  distal  while  pulling  the  mesial  end  with  the  other 
4 


50  THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

hand.  If  the  Hgature  has  been  well  waxed,  the  first  half  of  the 
knot  will  not  slip  or  loosen  ;  but  it  must  not  be  pulled  or  dis- 
turbed in  the  least  while  forming  the  other  half  of  the  knot. 
Let  the  ends  fall  perfectly  loose  while  forming  the  second  half 
and  work  it  up  carefully  until  it  is  just  right  and  then  draw  it 
tight  at  a  single  pull,  again  keeping  the  fingers  close  against  the 
arch,  both  to  the  mesial  and  distal.  A  ligature  tied  in  this  way 
will  always  be  tight  around  the  tooth. 

Rubber-Dam  Clamps. 

The  question  of  rubber- dam  clamps  is  always  a  troublesome 
one.  Nothing  is  entirely  satisfactory  in  all  positions.  The 
selection  on  the  list  is  as  good  for  the  purpose  as  can  be  had. 
With  them  all  can  be  done  that  clamps  will  do. 

In  filling  cavities  in  the  bicuspids  the  rubber  should  be 
secured  on  the  molar  tooth  distal  to  them  with  a  rubber-dam 
clamp.  The  bow  of  the  clamp  holds  the  rubber  out  of  the  way 
and  gives  space  and  a  better  view  of  the  field  of  operation.  In 
excavating  and  filling  cavities  in  the  molars  this  is  still  more  nec- 
essary. Whenever  practicable  the  clamp  should  be  placed  upon 
the  first  molar  for  operations  on  the  bicuspids,  and  on  the  second 
molar  for  operations  on  the  first  molar.  Generally,  in  operations 
on  the  second  molar  not  involving  the  distal  surface,  a  clamp  with 
a  bow  standing  well  to  the  distal  should  be  placed  on  the  same 
tooth  in  order  to  avoid  the  difficulty  of  placing  the  dam  on  the 
third  molar.  Rubber-dam  clamps  on  the  bicuspids  are  not  per- 
missible at  all  except  in  cases  where  the  molar  teeth  are  missing; 
and  even  then  they  are  of  doubtful  usefulness,  and  are  so 
unsteady  as  to  cause  the  patient  much  annoyance,  and  often 
considerable  pain. 

In  buccal  and  labial  cavities,  that  approach  near  to,  or  pass 
beyond  the  gingival  line,  the  special  clamp  should  be  used  on 
the  molars  and  the  Hatch  clamp  on  the  bicuspids  and  front' 
teeth.  Except  in  the  most  difficult  cases,  the  special  clamp  will 
answer  the  purpose  if  the  rubber,  after  being  placed  on  the 
tooth,  is  drawn  well  away  from  the  buccal  and  the  clamp 
applied,  or  if  the  clamp  is  put  on  first  and  the  rubber  passed 
over  it.  When  the  Hatch  clamp  is  applied  to  the  front  teeth 
with  labial  cavities,  the  rubber  must  be  drawn  well  away  from 
the  labial  surface  and  the  points  placed  in  position  and  the  set- 


THE    ENAMEL,  51 

screw  made  tight.      Then  the  rubber  may  be  allowed  to  draw 
tightly  around  it,  and  is  fairly  certain  to  exclude  moisture  per- 
•  fectly.      For  this  purpose  the  hole  in  the  rubber  should  be  cut  a 
little  larger  than  usual. 

With  the  most  skilful,  some  impossible  cases  occur  with  any 
and  all  of  these  instruments.  Then  resort  must  be  had  to  hold- 
ing the  dam  in  position  with  an  instrument  while  performing 
the  operation  with  the  other  hand.  This  is  difficult,  but  prac- 
ticable. The  best  instrument  for  this  purpose  is  a  straight  shaft 
with  a  broad  flat  point  cut  in  the  form  of  a  fork,  or  a  V-shaped 
notch. 

Often  in  proximate  cavities,  where  the  gingival  wall  is  very 
difficult  to  reach,  the  rubber  may  be  forced  into  position  and 
held  with  a  matrix,  or  the  matrix  may  be  placed  first  and 
securely  tied  and  the  rubber  applied  over  it.  Sometimes  a 
similar  device  will  accomplish  the  same  upon   buccal   surfaces. 

When  the  operation  is  completed,  great  care  should  be  had 
to  remove  all  ligatures  before  removing  the  rubber,  for  if  the 
rubber  is  pulled  away  with  a  ligature  on,  a  ring  of  rubber  will 
sometimes  be  torn  away  and  remain  around  the  neck  of  the 
tooth  unobserved,  and  do  great  damage  before  the  cause  is  dis- 
covered. When  the  contacts  between  the  teeth  are  close,  or 
when  gutta-percha  fillings  have  been  placed  to  seal  in  treat- 
ments, the  rubber  should  be  drawn  to  the  buccal  or  labial,  and 
the  septum  passing  between  the  teeth  cut  before  removing  the 
rubber.  This  will  avoid  the  danger  of  leaving  bits  of  rubber 
dam  hanging  between  the  teeth  or  of  disturbing  a  soft  filling. 
Finally,  when  the  rubber  has  been  removed,  the  gums  should 
be  well  kneaded  with  the  fingers,  while  being  flooded  with  warm 
water  from  the  syringe.  The  gums  have  been  compressed  and 
the  circulation  interfered  with,  and  this  will  clean  the  parts  and 
start  the  blood  into  full  activity  and  prevent  the  severe  soreness 
that  is  so  apt  to  follow. 

The    Enamel. 

The  structure  of  the  enamel  is  of  such  importance  in  its  rela- 
tion to  the  preparation  of  cavities  for  filling  that  it  requires  spe- 
cial study.  It  is  difiicult  to  so  prepare  specimens  of  the  enamel 
that  they  show  its  structure  well,  and  when  the  specimens  are 
well  prepared,  it  requires  a  large  amount  of  study  to  gain  that 


52  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

intimate  knowledge  of  it  that  is  necessary  to  the  most  intelhgent 
practice  in  filling  operations. 

The  enamel  when  examined  macroscopically  appears  as  a 
very  hard,  vitreous  body,  white,  or  a  bluish-white,  very  dense 
and  brittle,  in  which  no  traces  of  structure  can  be  determined. 
It  cuts  with  much  difficulty,  and  is  much  inclined  to  chip  and 
crumble.  If,  however,  it  is  examined  with  a  good  hand  magni- 
fying glass,  certain  striations  can  be  observed  that  give  a  sugges- 
tion of  histological  structure. 

Although  the  enamel  seems  to  be  opaque,  or,  at  most,  trans- 
lucent, by  ordinary  examination,  it  is  found  to  be  almost  as  trans- 
parent as  glass  when  ground  into  thin  sections.  When  so 
prepared,  very  little  of  the  structure  can  be  seen  with  the  micro- 
scope usually,  without  some  preparation  that  will  cause  its  histo- 
logical elements  to  appear.  It  is  largely  for  this  reason  that  so 
little  is  seen  of  the  structure  of  enamel  in  the  sections  ordinarily 
prepared  for  microscopic  observations. 

Histological   Characters    of    the    Enamel     in    Relation   to 
the    Preparation    of  Cavities. 

Enamel  is  composed  of  rods  or  fibers  cemented 
together  by  an  intervening  cement  substance.  These  rods 
and  cement  substance  are  very  nearly  of  the  same  density,  so  that 
when  examined  in  the  perfect  state  the  enamel  seems  to  be  almost 
homogeneous,  or  without  special  structure.  In  the  most  perfect 
specimens  of  enamel  only  a  striation  suggesting  structure  can  be 
seen.  It  has  been  learned,  however,  that  the  cement  substance 
between  the  rods  by  which  they  are  united  dissolves  more  readily 
in  acids  than  the  rods  themselves.  We  may  avail  ourselves  of 
this  fact,  and  partially  isolate  the  rods  by  solution  of  the  cement 
substance  with  very  dilute  hydrochloric  or  lactic  acid,  and  in  that 
way  obtain  good  views  of  them.  We  can  not,  however,  carry 
this  solution  very  far,  for  the  reason  that  the  rods  will  also  be 
dissolved,  and  the  whole  tissue  disappear.  Still,  by  working 
carefully  with  very  dilute  acids,  good  fragments  of  the  rods  may 
be  obtained. 

The  enamel  rods  seem  to  be  made  up  of  globules  or  little 
balls  pressed  together  in  a  single  row  or  line,  forming  the  rod. 
One  can  readily  copy  this  formation  by  taking  small  balls  of  soft 
clay  and  pressing  one  upon  the  other,  forming  a  rod.      In  some 


THE    ENAMEL,  53 

enamel  these  globular  forms  are  very  prominent  in  the  apparent 
make-up  of  the  rod,  while  in  some  other  specimens  these  globules 
are  so  perfectly  fused  together  and  smoothed  as  to  almost  dis- 
appear ;  we  then  have  a  smooth  enamel  rod.  This  latter  is 
rather  the  exception  than  the  rule. 

The  enamel  rods  are  stronger  than  the  cement  sub- 
stance, so  that  in  any  attempt  to  break  up  or  cut  the  enamel  it 
is  inclined  to  split  along  the  length  of  the  rods.  Then,  since 
the  enamel  is  very  hard  and  difficult  to  cut,  a  knowledge  of  the 
direction  of  the  rods  becomes  of  first  importance  in  any  attempt 
to  form  cavities  in  teeth.  These  rods,  while  hard  to  cut,  are, 
when  they  are  parallel,  very  easy  to  split  apart.  Indeed,  much 
of  human  enamel  will  split  almost  as  easily  as  straight-grained 
pine,  if  the  force  is  applied  in  just  the  right  direction.  This  is 
because  the  cementing  substance  that  cements  the  rods  together 
is  much  weaker  than  the  rods  themselves.  In  other  specimens 
of  enamel  the  rods,  instead  of  lying  parallel  with  each  other, 
are  very  much  interwoven  and  twisted  together  ;  so  much  so, 
indeed,  as  to  prevent  them  being  readily  split  apart.  This 
enamel,  instead  of  splitting  like  straight-grained  pine,  is  more 
like  the  pine  knot,  which  is  very  difficult  to  split  or  cut,  as  com- 
pared with  the  straight-grained  wood.  Formerly  it  was  sup- 
posed that  this  difference  in  the  enamel  to  cutting  instruments 
was  due  to  a  greater  amount  of  lime  salts,  or  the  hardening  ele- 
ment. We  have  learned  in  recent  years,  however,  that  this  is 
not  the  case.  The  one  contains  no  greater  proportion  of  lime 
salts  than  the  other  and  will  not  resist  decay  any  better.  But 
the  difference  is  due  wholly  to  the  difference  in  the  relative  inter- 
lacing of  the  enamel  rods. 

This  interlacing  or  twisted  form  of  enamel  is  usually 
confined  to  the  inner  half  of  its  thickness.  While  in  the 
outer  half  of  the  enamel  the  rods  are  parallel  and  will  split  apart 
readily,  the  rods  of  the  inner  half  are  interwoven  or  twisted  in 
such  a  way  as  to  prevent  splitting.  Therefore,  when  a  chisel  or 
enamel  hatchet  is  applied  for  the  purpose  of  splitting  it  off  it  will,- 
if  supported  by  sound  dentin,  split  but  about  half  way,  and  the 
remaining  half  of  the  thickness  is  removed  with  great  difficulty. 
It  is  then  almost  a  necessity  that  we  undermine  this  by  cutting 
away  the  dentin  from  beneath  it,  after  which  we  may  break  it 
down  f|uite  reachly. 


54  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

The  enamel  rods  are  almost  always  parallel  AA/^ith 
each  other  in  the  outer  half  or  near  the  surface  of  the 
enamel.  This  fact  you  should  observe  carefully,  for  it  is  of  the 
utmost  importance  in  the  preparation  of  the  enamel  margins  of 
cavities.  All  that  we  have  said  of  the  splitting  apart  of  the 
enamel  rods  applies  with  all  of  its  force  to  this  outer  portion  of 
the  enamel,  no  matter  how  much  the  rods  may  be  twisted  in  the 
deeper  portions,  and  for  this  reason  the  enamel  margins  of  cavi- 
ties should  be  so  prepared  that  no  portion  of  the  cavo-surface 
angle  will  present  short  ends  or  rods  unsupported;  that  is,  the 
enamel  wall  should  be  parallel  with  the  length  of  the  rods,  and 
the  bevel  of  the  cavo-surface  angle  should  cut  off  the  ends  so 
that  there  may  be  no  loose  ends  of  rods  upon  the  surface  to  fall 
away  while  packing  gold  or  after  finishing  the  filling.  This  may 
readily  be  accomplished  if  we  know  the  direction  of  the  enamel 
rods. 

The  direction  of  the  rods  may  be  known,  first,  by  obtaining 
a  good  general  knowledge  of  their  course  by  the  study  of  pre- 
pared sections  of  enamel;  second,  by  observing  the  direction  of 
cleavage  during  the  preparation  of  cavities.  By  the  term  cleav- 
age we  express  the  tendency  of  a  substance  to  split  or  separate 
in  given  directions.  The  direction  of  cleavage  is  the  direction  in 
which  it  splits  most  readily.  Therefore,  for  our  purposes  the 
terms  cleavage  and  splitting  are  practically  synonymous. 

It  may  be  stated  as  a  general  rule  that  the  direction  of  the 
enamel  rods  is  from  the  center  of  the  crown  of  the  tooth 
tow^ard  the  surface.  Everywhere  on  the  crown  of  the  tooth 
the  ends  of  the  enamel  rods  present  to  the  surface.  Over  the 
greater  portion  of  the  crown  the  direction  of  the  enamel  rods  is 
perpendicular  to  the  surface,  but  in  every  tooth  there  are  certain 
portions  in  which  the  enamel  rods  approach  the  surface  at  a  more 
or  less  considerable  inclination. 

If  we  draw  a  line  around  the  crown  of  a  molar  or  bicuspid 
tooth  in  the  middle  of  its  length  and  examine  the  enamel  rods 
in  that  section  we  will  find  them  everywhere  very  nearly  perpen- 
dicular to  the  plane  of  the  surface.  If  we  move,  now,  gradu- 
ally, toward  the  cusps  of  the  tooth  we  will  find  the  direction  of 
the  enamel  rods  progressively  leaving  the  perpendicular  and 
inclining  toward  the  cusps.  This  inclination  becomes  continually 
greater,  until  when  the  point  of  the  cusp  is  reached  the  direc- 


THE    ENAMEL. 


tion  of  the  enamel  rods  is  parallel  to  the  length  of  the  cusp,  or, 
in  other  words,  the  direction  of  the  rods  is  perpendicular  to  the 
surface  of  the  tip  or  point  of  the  cusp. 

If  from  this  line  around  the  crown  of  the  molar  or  bicuspid 
in  the  center  of  its  Length  we  approach  one  of  the  marginal 
ridges  of  the  occlusal  surface,  we  will  also  find  the  direction  of 
the  enamel  rods  inclining  toward  the  marginal  ridge  in  such  a 
way  that  as  we  pass  over  the  marginal  ridge  the  direction  is  so 
changed  that  the  rods  stand  perpendicular  to  the  occlusal 
surface. 

If  the  attempt  be  made  to  prepare  a  cavity  upon  an  axial 
surface  of  one  of  these  teeth  for  filling,  and  this  cavity  ap- 
proaches a  cusp  or  a.  marginal  ridge,  the  enamel  wall  must  be 
inclined  outward  Tor  toward  the  occlusal)  very  gready,  or  else 
short  ends  of  enamel  rods  will  be  left  at  the  surface.  And  if 
inclined  enough  to  prevent  this,  the  filling  material  will  be  so 
thin  at  its  margin  that  it  will  not  have  sufficient  strength. 
These  facts  forbid  us  laying  enamel  margins  near  the 
occlusal  margins  of  the  axial  surfaces  of  the  teeth. 

If  now,  we  proceed  from  the  center  of  the  length  of  the 
crown  of  the  molar  or  bicuspid  toward  the  gingival  line,  we  will 
find  the  direction  of  the  enamel  rods  again  deviating  from  the 
perpendicular  and  inclining  toward  the  gingival  line.  This 
inclination  is  much  less  in  extent,  however,  but  more  variable 
than  that  found  in  passing  toward  the  marginal  ridges  of  the 
occlusal  surfaces.  The  inclination  at  the  gingival  line  is  usually 
about  six  centigrades,  often  less,  and  the  greatest  that  I  have 
observed  has  not  been  more  than  ten  centigrades.  An  inclina- 
tion of  six  centigrades  is  readily  overcome  by  inclining  the 
enamel  wall,  or  even  twelve  centigrades  inclination  of  this  part 
of  the  enamel  wall  can  readily  be  made  and  the  filling  material 
be  sufficiently  strong  for  the  locality. 

On  examination  of  the  occlusal  surface  of  a  molar  or  bicus- 
pid we  find  a  tendency  of  the  enamel  rods  to  incline  somewhat 
toward  the  pits  and  grooves,  and  especially  do  they  incline 
toward  open  pits  or  fissured  grooves.  If  the  grooves  are  well 
closed  and  shallow,  there  will  be  less  inclination  toward  them. 

As  we  pass  from  the  pits  and  grooves  toward  the  cusps  the 
direction  of  the  rods  first  becomes  perpendicular  to  the  surface 
and  then  begins  to  incline  toward  the  cusps,  and  when  we  arrive 


56  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

at  the  point  of  the  cusps  the  direction  will  be  perpendicular  to 
the  surface  at  the  immediate  point  of  the  cusp.  Or,  if  we  follow 
the  direction  of  the  rods  passing  from  the  fossae  of  the  occlusal 
surface  to  the  marginal  ridges,  mesial  and  distal,  we  find  the 
direction  of  the  rods  first  deviating  from  the  perpendicular 
toward  the  center  of  the  fossae,  but  as  we  pass  toward  the  mar- 
ginal ridges  the  deviation  is  toward  the  marginal  ridges,  until, 
when  we  arrive  near  the  crest  of  the  ridge,  the  direction  of  the 
inclination  is  decidedly  toward  the  ridge. 

Therefore,  in  the  preparation  of  cavities  in  the  occlusal  sur- 
faces of  these  teeth  the  enamel  wall  may  be  cut  perpendicular  to 
the  general  plane  of  the  occlusal  surface,  so  long  as  the  enamel 
margin  does  not  approach  too  closely  to  cusps  or  the  marginal 
ridges,  for  a  slight  bevel  of  the  cavo-surface  angles  will  insure 
a  solid  margin  without  any  short  ends  of  rods.  But  if  the 
cusps  or  the  marginal  ridges  are  closely  approached  the  inclina- 
tion of  the  enamel  wall  should  be  toward  the  ridge  and  the  cavo- 
surface  angle  beveled  rather  more  strongly  in  order  to  insure  the 
removal  of  all  short  ends  of  enamel  rods,  and  to  secure  a  firm 
margin. 

In  the  incisors  and  cuspids,  if  we  draw  a  line  around  the 
crown  at  the  junction  of  the  middle  and  gingival  third,  we  will 
find  the  enamel  rods  perpendicular  to  the  surface  upon  the 
mesial,  distal  and  labial  surfaces,  and  generally  nearly  so  upon 
the  lingual  surface.  In  these  teeth  the  direction  of  the  enamel 
rods  at  the  junction  of  the  middle  and  gingival  third  of  the  lin- 
gual surface  is  very  variable,  because  of  the  differences  of  the 
prominence  of  the  linguo-gingival  ridge  and  the  depth  of  the 
grooves  of  the  lingual  surface.  In  cases  in  which  the  linguo- 
gingival  ridge  is  prominent  and  the  grooves  deep,  or  fissured,  ' 
there  will  be  a  strong  inclination  of  the  enamel  rods  toward  the 
grooves.  If,  on  the  other  hand,  this  surface  is  smooth  and  even, 
with  the  grooves  perfectly  closed,  so  as  not  to  be  apparent,  the 
direction  of  the  enamel  rods  will  be  perpendicular  to  the  surface. 

As  we  pass  from  the  junction  of  the  middle  and  gingival  third 
of  the  crown  toward  the  incisal  margin  of  the  lingual  surface, 
the  inclination  of  the  enamel  rods  is  more  and  more  toward  the 
incisal.  At  the  junction  of  the  middle  and  incisal  third  the 
inclination  is  from  six  to  twelve  centigrades,  and  in  the  incisal 
third  it  often  is  fifteen  or  eighteen  centigrades  before  the  incisal 


THE    ENAMEL. 


57 


edge  is  reached.  This  very  strong  inclination  of  the  enamel 
rods  toward  the  incisal  upon  this  surface  renders  it  exceedingly- 
difficult  to  make  good  margins  if  the  marginal  lines  of  the  cavity 
approach  nearer  the  incisal  edge  than  the  junction  of  the  middle 
and  incisal  thirds  of  the  crown.  If  the  cavo-surface  angle  of 
the  enamel  is  beveled  enough  to  remove  all  short  ends  of  enamel 
rods  the  filling  material  becomes  too  thin  to  stand  well.  This  is 
the  reason  we  so  frequently  see  imperfect  margins  when  the 
marginal  lines  of  fillings  have  been  laid  inthis  position. 

On  the  labial  surface  of  the  incisors  and  cuspids,  the 
direction  of  the  enamel  rods  is  generally  about  perpendicular  to 
the  surface  of  the  junction  of  the  middle  and  gingival  third,  and 
as  the  incisal  margin  of  the  surface  is  approached  there  is  a 
gradual  inclination  toward  the  incisal.  This  change  is  slow  in 
the  middle  third,  so  that  it  is  rarely  more  than  six  centigrades 
at  the  junction  of  the  middle  and  incisal  thirds.  In  the  incisal 
third  the  increased  inclination  to  the  incisal  is  much  more  rapid, 
so  that  upon  the  incisal  edge  the  direction  of  the  enamel  rods  is 
parallel  to  the  long  axis  of  the  tooth.  These  directions  of  the 
rods  must  be  taken  into  account  in  any  case  in  which  the  mar- 
ginal lines  of  labial  cavities"  approach  the  incisal  margin  of  the 
surface.      Fortunately,  such  cavities  are  rare. 

On  the  mesial  and  distal  surfaces  the  direction  of  the 
enamel  rods  is  generally  perpendicular  to  the  surface  through- 
out the  middle  third  of  the  length  of  the  crown.  In  the  incisal 
third  an  inclination  toward  the  angle  begins.  The  extent  of 
this  is  quite  variable.  The  rule  is  that  the  more  acute  the  angle 
the  closer  the  angle  is  approached  before  the  inclination  of  the 
rods  toward  the  angle  becomes  pronounced.  Therefore,  the 
distal  angle  being  more  rounded  the  inclination  of  the  rods 
toward  it  begins  further  from  the  angle  upon  the  distal  surface, 
but  often  approaches  the  angle  quite  closely  upon  the  mesial 
before  the  inclination  becomes  great.  For  this  reason  cavity 
lines  in  mesial  surfaces  may  approach  safely  quite  close  to  the 
incisal  angle  if  the  enamel  is  well  supported  by  sound  dentin. 
In  the  distal  surfaces  much  more  care  must  be  exercised  in  lay- 
ing cavity  lines  close  to  the  incisal  angle,  for  the  reason  that  if 
the  enamel  wall  is  inclined  enough  to  give  a  good  cavo-surface 
angle  the  edge  of  the  filling  is  likely  to  become  too  thin  to  stand 
well. 


58  THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

In  following  the  inclination  of  the  enamel  rods  around  the 
incisors  and  cuspids  in  the  circumferential  direction,  we  find 
them  generally  standing  perpendicular  to  the  surface.  A  notable 
exception  to  this  is  the  approach  to  the  mesial  and  distal  marginal 
ridges  on  the  lingual  surface  and  over  the  lingual  marginal  ridges. 
Here  the  enamel  rods  incline  somewhat  toward  the  marginal 
ridges,  but  in  passing  over  these  ridges  their  direction  or  inclina- 
tion changes  rather  suddenly.  For  this  reason  this  becomes 
rather  a  dangerous  point  in  the  preparation  of  proximate  cavities 
in  the  incisors.  When  the  marginal  lines  of  these  proximate 
cavities  reach  to  the  lingual  marginal  ridge,  it  is  rarely  safe  to 
leave  any  of  the  ridge  remaining,  because  of  the  very  uncertain 
direction  of  the  enamel  rods.  Especially  is  this  true  of  lateral 
incisors,  in  which  the  curve  of  the  ridge  is  often  very  abrupt. 
While  this  ridge  is  very  strong  in  the  perfect  tooth,  it  becomes 
very  frail  when  its  support  on  either  side  has  been  destroyed, 
and  the  only  safe  course  seems  to  be  to  cut  it  away  sufficiently  to 
be  certain  of  the  direction  of  the  enamel  rods  upon  the  margin 
formed.  The  rounding  of  the  labio-mesial  or  labio-distal  angles 
is  not  so  abrupt,  and  the  enamel  rods  usually  hold  closely  to  a 
direction  perpendicular  to  the  surface,  so  that  good  margins  can 
be  made  at  any  point  by  observing  carefully  the  form  of  the 
tooth  and  the  enamel  cleavage. 

In  passing  toward  the  gingival  line  from  the  junction  of  the 
middle  and  gingival  third  of  the  length  of  the  crown,  the  inclina- 
tion of  the  enamel  rods  changes  more  and  more  toward  the 
gingival.  This  varies  considerably  in  different  specimens  ;  gen- 
erally it  is  not  much  more  than  six  or  eight  centigrades  at  the 
gingival  margin  of  the  enamel,  but  in  some  specimens  it  is  ten 
or  twelve  centigrades.  This  calls  for  extreme  care  in  beveling 
gingival  cavo-surface  angles  in  cavities  that  approach  close  to 
the  gingival  line. 

How  to  Study  the  Direction  and  Inclination  of  the  Enamel 

Rods. 

The  first  studies  of  the  enamel  rods  should,  of  course,  be 
made  by  grinding  sections  and  studying  these  with  the  aid  of  the 
microscope,  and  in  lantern  illustrations.  But  when  a  fairly  good 
idea  of  the  structure  has  been  obtained  in  this  way  it  is  better  to 
continue  the  study  by  noting  carefully  the  cleavage  of  the  enamel 


THE    ENAMEL.  59 

while  operating  at  the  chair.  In  preparing  cavities  one  is  han- 
dHng  the  enamel  all  the  time,  and  by  noting  the  direction  of  the 
cleavage  and  remembering  that  this  cleavage  follows  the  length 
of  the  enamel  rods,  may  be  continuously  studying  their  direction 
in  ditTerent  positions  upon  any  and  all  of  the  teeth.  This  study, 
when  pursued  for  some  time,  enables  an  operator  to  so  place  his 
instruments  as  to  split  ofif  the  enamel  easily  in  opening  cavities, 
which  is  of  immense  advantage  in  this  work,  as  he  will  do  it 
easier  and  quicker.  The  operations  will  also  be  greatly  improved 
because  of  more  perfect  preparation  of  the  enamel  margins.  He 
will  come  to  know  very  perfectly  the  direction  of  the  rods,  and 
the  proper  inclination  of  the  enamel  wall  in  all  positions. 

One  soon  learns  to  feel  for  the  direction  of  the  enamel 
rods  with  his  cutting  instruments  and  to  take  advantage  of  the 
cleavage  in  cutting  the  enamel,  and  then  readily  feels  this  in 
the  formation  of  the  enamel  wall  and  its  cavo-surface  angle,  and 
knows  when  his  enamel  margin  is  firm  and  strong.  Carry  on 
the  study  at  the  chair  and  become  a  rapid  and  strong  operator. 

The  shaving  up  of  the  enamel  in  forming  the  enamel  wall 
should  be  looked  to  with  great  care.  Those  points  at  which  the 
enamel  rods  are  more  or  less  broken  apart  will  generally  appear 
a  little  whitish,  and  in  pushing  a  sharp  edge  lighdy  along  them 
the  loosened  rods  are  easily  dislodged  in  what  appears  as  a  fine 
powder.  By  continuing  this  shaving  motion  the  enamel  wall 
will  become  clear,  and  have  a  firm,  vitreous  appearance. 
This  condition  of  the  enamel  wall  should  always  be  obtained  in 
finishing  the  preparation  of  the  cavity. 

In  the  study  of  the  enamel  in  sections  and  on  the  screen,  it 
has  been  seen  that  the  lines  of  the  grooves  are  weak  lines  on 
account  of  the  imperfect  fusion  of  the  enamel  plates  in  coming 
together  during  development.  This  is  true  even  in  those  grooves 
that  are  most  perfecdy  closed.  But  in  very  many  cases  they  are 
imperfectly  closed,  so  that  along  these  lines  the  enamel  has  no 
strength. 

It  should,  therefore,  be  the  rule  that,  when  in  the  prepara- 
tion of  a  cavity  the  marginal  lines  must  approach  near 
a  groove,  cut  to  the  groove  or  past  it. 

This  rule  should  be  regarded  as  applying  in  all  positions  upon 
the  teeth  if  the  cavity  margin  is  parallel,  or  very  nearly  parallel, 
with  the  groove.      For  instance,  I  will  mention  that  in  preparing 


60  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH, 

large  cavities  in  the  distal  surfaces  of  upper  molars  the  disto- 
lingual  groove  is  often  approached.  In  any  such  case  cut  to  the 
groove  until  it  has  passed  over  the  ridge  to  the  lingual  surface, 
when  its  direction  is  more  to  the  mesial,  and  then  break  away 
from  it  rather  suddenly,  forming  a  kind  of  step,  if  the  enamel  of 
this  portion  of  the  lingual  surface  is  well  supported  by  sound 
dentin. 

If  the  mesio-buccal  angle  of  a  molar  is  so  decayed  as  to  make 
the  removal  of  a  considerable  part  of  it  necessary,  cut  to  the  buc- 
cal groove,  for  if  this  is  not  done  the  intervening  portion  of 
enamel  is  very  likely  to  break  away. 

The  same  rule  applies  to  the  triangular  grooves  of  the  bicus- 
pids that  pass  to  the  buccal  surface  to  the  mesial  and  distal  of  the 
buccal  cusps.  If  in  any  case  the  angles  of  these  teeth  are  so 
injured  that  the  cavity  lines  should  approach  near  these  grooves, 
cut  to  the  grooves. 

In  any  case  in  which  the  angle  of  an  incisor  must  be  removed, 
cut  to  the  labial  groove,  whether  it  be  mesial  or  distal.  This  is 
for  the  reason  that  the  lines  of  the  grooves  are  weak  lines,  and 
the  enamel  is  likely  to  break  along  these  lines. 

These  cases  will  sufficiently  illustrate  this  rule. 

Excavation  of  Cavities  by  Classes. 

Note.  —  The  determination  of  the  conditions  calling  for 
filling  operations  is  largely  dependent  upon  pathological  pro- 
cesses. As  it  is  the  intention  to  confine  this  book  as  strictly  as 
possible  to  the  technical  procedures  of  filling  operations,  these 
pathological  processes  will  not  be  discussed.  Here  we  can  only 
take  note  of  the  physical  conditions  presented  by  individual 
teeth,  leaving  pathological  processes  related  to  them  to  be  taken 
up  at  another  time. 


Class  I. —  Cavities  beginning  in  structural  defects  in 
the  teeth,  as  pits  and  fissures. —  These  occur  in  the  occlusal 
surfaces  of  the  molars  and  bicuspids,  in  the  occlusal  half  of  the 
buccal  surfaces  of  the  molars,  or  in  the  buccal  pits,  more  rarely 
in  the  lingual  portion  of  the  disto-lingual  groove  of  the  upper 
molars,  and  in  the  lingual  surfaces  of  the  upper  incisors  ;  most 
frequent  in  the  laterals. 


EXCAVATION    OF    CAVITIES    PA"    CLASSES.  01 

The  primary  physical  condition  leading  to  the  location 
of  caries  in  these  positions  is  a  foult,  or  imperlection  in  the 
enamel — an  imperfect  closure  of  the  enamel  plates  —  which 
leaves  an  opening  of  more  or  less  depth  as  a  pit  or  fissure,  and 
it  is  in  these  that  decay  starts.  The  surface  of  the  enamel  in 
the  immediate  neighborhood  of  these  is  fully  exposed  to  the 
friction  of  mastication  and  is  kept  well  cleaned.  For  this 
reason  there  is  no  disposition  to  the  spreading  of  the  carious 
process  upon  the  surface  of  the  enamel.  Therefore,  these 
cavities  all  belong  to  the  class  which  do  not  require  extension  of 
the  cavity  outiines  for  the  prevention  of  the  recurrence  of  decay. 
All  the  extension  that  is  necessary  is  such  cutting  away  of  the 
cavity  walls  as  will  fully  uncover  the  carious  area  and  present  a 
surface  upon  which  a  good,  smooth  finish  of  the  filling  can  be 
made.  In  order  that  this  good,  smooth  finish  may  be  made,  it 
is  necessary  that  all  sharp  grooves  connecting  with  the  cavity  be 
cut  out  to  a  point  where  the  enamel  is  sufficiently  level. 

Pit  Cavity  in  Central  Fossa  of  an  Upper  First  Molar  No.  I. 

Description. —  Upon  examination  a  small  pit  in  the  enamel 
is  found  and  the  point  of  the  exploring  instrument  passes 
through  it  into  the  dentin,  which  seems  to  be  softened,  show  ing 
that  caries  has  begun.  The  surface  of  the  enamel  about  the  pit 
is  clear  and  clean.  The  buccal  groove  is  deep  and  sharp,  but 
the  mesial  and  distal  grooves  are  shallow,  fairly  smooth,  and 
well  closed. 

Procedure. —  A  round  bur,  A  millimeters  in  diameter,  in 
the  engine,  is  placed  in  the  pit  while  in  rotation  and  fairly  strong 
pressure  applied,  while  the  hand-piece  is  swayed  to  and  fro.  In 
most  cases  the  bur  will  cut  through  the  enamel  and  enter  the 
cavity  within  a  few  seconds.  If  it  does  not  do  so  promptly,  it 
should  be  removed  for  a  moment  and  allowed  to  cool  —  for  heat 
will  develop  quickly  —  and  then  reapplied  in  the  same  manner. 
This  should  be  repeated  until  the  bur  passes  through  the  enamel 
and  enters  the  softened  dentin.  Immediately  this  occurs,  the 
bur  should  be  removed  from  the  hand-piece  and  a  bur,  i  mil- 
limeter in  diameter,  chosen.  This  is  passed  through  the  opening 
into  the  dentin  in  the  same  way,  thus  enlarging  the  opening  in 
the  enamel.  This  is  then  exchanged  for  a  larger  bur,  i  i^o  mil- 
limeters in  diameter,  which  is  also  passed  through  the  opening. 


62  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

This  completes  the  use  of  the  round  bur,  and  it  is  the  only  use 
made  of  it  in  excavating  cavities.  An  examination  should  now 
be  made  with  a  curved  explorer  to  determine  more  nearly  the 
extent  of  the  decay  in  the  dentin.  In  case  no  softened  dentin 
extending  laterally  under  the  enamel  is  found,  the  rubber  dam 
should  be  applied  and  an  inverted  cone  bur,  equal  in  size  With 
the  last  round  bur  used,  should  be  introduced,  and  with  its 
square  end  the  remaining  decay  should  be  removed,  and  the 
floor,  or  pulpal  wall  of  the  cavity  made  flat.  Now,  with  hoe 
12-5-6  used  as  a  chisel  (straight  chisel  10  or  binangle  chisel 
10-6-6  may  be  substituted),  the  enamel  is  chipped  away  along 
the  buccal  groove  as  far  as  it  will  readily  split  off".  Then  an 
inverted  cone  bur,  10  millimeters  in  diameter,  is  passed  into  the 
cavity  and  made  to  enter  the  dentin  just  beneath  the  dento- 
enamel  junction  toward  the  buccal  groove,  and  slowly  drawn  to 
the  surface  of  the  enamel.  It  is  then  entered  again  at  the  same 
point,  and  this  motion  repeated,  making  cut  after  cut,  following 
the  line  of  the  groove,  until  the  groove  has  been  opened  to  a 
point  where  it  is  sufficiently  shallow,  or  the  surface  of  the  enamel 
is  sufficiently  level  for  a  good  finish  of  a  filling  to  be  made. 
Often  it  will  be  necessary  to  follow  this  groove  to  the  crest  of  the 
marginal  ridge.  This  done,  chip  away  the  mesial  and  distal 
walls  of  the  slot  formed,  with  straight  chisel  15  or  20,  sufficiently 
to  remove  the  inclines  of  the  buccal  groove,  after  which  pass  a 
large  inverted  cone,  or  a  fissure  bur  (ito  millimeters),  through 
the  slot,  and  make  its  floor  square  and  flat,  and  smooth  up  the 
walls. 

A  very  careful  examination  should  now  be  made  of  all  parts 
of  the  walls  of  the  cavity.  If  any  softened  dentin  is  found,  the 
enamel  should  be  chipped  from  over  it  with  hoe  12-5-6  or  chisel 
10,  the  softened  area  removed  and  the  pulpal  wall  of  the  cavity 
squared  out  to  the  increased  area. 

The  outline  of  the  cavity  should  now  be  re-examined  to  see 
whether  every  part  of  the  margin  is  sufficiently  level  to  permit  a 
good  finish  of  the  filling  when  this  has  been  placed,  and  if  irreg- 
ularities occur  that  would  prevent  a  smooth  finish,  the  cavity  must 
be  sufficiently  extended  to  obtain  conditions  that  will  allow  a 
good,  smooth  finish  of  all  parts  of  the  margin  to  be  made. 

The  finish  of  the  enamel  wall  is  now  to  be  made  by 
careful  paring  or  planing  with  a  sharp  chisel.     So  far  as  possible 


EXCAVATION    OF    CAVITIES    BY    CLASSES.  G3 

the  mo\ement  of  the  edge  of  the  chisel  should  be  in  the  direc- 
tion of  the  length  of  the  margin,  or  around  the  cavity.  In  such 
a  cavity  as  this,  both  the  dentin  and  enamel  walls  may  be  per- 
pendicular and  the  opposing  walls  parallel.  The  enamel  rods 
will  be  inclined  toward  the  cavity  in  every  part,  and  no  outward 
inclination  of  the  enamel  walls  is  necessary.  The  cavo-surface 
angle  of  the  entire  margin  should  be  slightly  beveled  to  dirninish 
the  danger  of  fracture  in  placing  the  filling  material.  In  such  a 
cavity  no  starting  points  for  beginning  the  filling  are  required, 
and  no  further  preparation  for  retention  of  the  filling  is  necessary, 
except  to  see  that  the  opposing  walls  are  parallel. 

Variations. —  It  will  often  happen  that  in  a  cavity  of  this 
description  a  considerable  area  of  decayed  dentin  will  be  found 
beneath  the  enamel  after  the  burs  have  been  passed  through  into 
it.  In  this  case  the  overhanging  enamel  must  be  chipped  away 
with  hoe  12-5-6  or  chisel  10  or  15,  until  sound  dentin  is  reached 
in  every  direction.  When  this  has  been  done,  the  remaining 
portion  of  the  buccal  groove  should  be  cut  out  as  described,  first 
completing  the  outline  of  the  cavity.  Then,  if  the  area  has 
become  considerable,  the  remaining  decay  is  best  removed  with 
spoons  1 5-8- 1 2  or  20-9-12,  as  may  best  suit  the  size  of  the  cav- 
ity. Enter  the  blade  beneath  the  softened  material,  close  against 
the  enamel  wall  at  the  lingual  or  buccal  side,  and  force  it  with 
a  strong  thrust  in  a  curved  direction  to  the  other  side  of  the 
cavity  ;  two  or  three  strokes  well  made  should  be  sufficient. 
Then  square  up  the  pulpal  wall  so  that  its  angles  with  the  sur- 
rounding walls  are  sharp  and  definite,  using  hoe  12-5-6  or,  in 
some  positions,  hoe  1 2-5-1 2,  with  a  scraping  motion.  In  many 
cases  this  will  be  as  conveniently  and  accurately  done  with  a 
square-ended  fissure  bur,  i  /,?  millimeters  in  diameter,  or  with  the 
inverted  cone  bur.  In  this  use  of  the  bur,  the  shaft  should  be 
held  parallel  with  the  long  axis  of  the  tooth,  so  that  the  square 
end  of  the  bur  will  cut  the  pulpal  wall  of  the  cavity  flat  and 
make  its  angles  with  the  surrounding  walls  sharp  and  definite. 
Finish  the  enamel  wall  and  cavo-surface  angle  the  same  as  before. 
In  many  cases  the  mesial  groove  will  be  so  sharp  and  deep  that 
it  will  require  cutting  out  well  toward  the  mesial  marginal  ridge. 


64  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

Pit  Cavity  in  Central    Fossa  of    Upper   First  Molar  No.  2. 

Description. —  The  pit  is  open  so  that  the  exploring  instru- 
ment readily  passes  in,  giving  room  to  be  turned  about,  revealing 
a  considerable  decayed  area ;  some  discoloration  shows  through 
the  enamel. 

Procedure. —  Begin  the  excavation  by  chipping  away  the 
overhanging  enamel  with  straight  chisel  15.  Or,  if  the  orifice 
in  the  enamel  is  still  very  small,  begin  with  straight  chisel  10, 
and  use  the  15  later.  This  may  be  done  by  hand  pressure,  but 
mallet  pressure  is  much  better.  Continue  this  chipping  as  far  as 
the  enamel  can  be  readily  cut  in  this  way,  or  until  sound  dentin 
is  found  supporting  the  enamel  at  every  point.  Now  look  care- 
fully to  the  relations  of  the  outline  of  the  cavity  to  the  surface, 
and  proceed  at  once  to  cut  out  any  grooves  that  will  interfere 
with  a  perfect  finish  of  the  filling.  Now  take  hatchet  8-3-23,  or, 
if  the  opening  into  the  cavity  is  too  small  for  this,  take  hatchet 
6-2-23,  and  sweep  its  edge  around  the  dentin  wall  of  the  cavity 
with  a  few  vigorous  strokes,  loosening  up  and  partially  removing 
the  softened  material  from  them,  and  see  whether  or  not  there  are 
some  points  at  which  decay  extends  beneath  the  enamel.  If  such 
are  found,  clip  the  enamel  from  over  them  and  perfect  the  cav- 
ity outline.     At  this  point  the  rubber  dam  should  be  adjusted. 

The  next  step  should  be  to  square  up  the  dentin  walls.  If 
there  is  a  considerable  mass  of  decay  obscuring  the  cavity,  it 
may  be  first  removed  roughly  by  a  few  vigorous  strokes  with 
spoons  20-9-12. 

In  squaring  up  the  dentin  walls  a  square-end  fissure  bur 
(irV  millimeters)  may  be  used  in  cases  in  which  this  may  be 
brought  parallel  with  the  long  axis  of  the  tooth,  which  can  gen- 
erally be  done  in  the  occlusal  cavities  in  the  first  molars  and 
bicuspids.  This  is  placed  with  its  end  upon  the  pulpal  wall, 
and,  while  rotating,  pressed  laterally  against  one  of  the  sur- 
rounding walls,  and  carried  around  the  whole  cavity  in  a  series 
of  cuts.  This  will  square  up  the  surrounding  dentin  walls  to  the 
enamel  walls,  and  its  square  end  will  leave  the  pulpal  wall  flat, 
and  its  angles  with  the  surrounding  walls  sharp  and  definite. 
This  is  to  be  taken  as  the  plan  of  squaring  up  the  sur- 
rounding and  pulpal  walls  (and  axial  walls  in  buccal  and 
labial  cavities)  when  burs  are  used  for  that  purpose. 


EXCAVATION    OF    CAVITIES    BY    CLASSES.  65 

In  doing  this,  care  should  be  had  not  to  continue  any  single 
cut  so  long  as  to  develop  considerable  heat.  Often  much  unnec- 
essary pain  is  produced,  and  occasionally  serious  injury  done  to 
the  pulp  of  the  tooth  by  the  heat  developed  by  rapidly  rotating 
burs.  Also  care  must  be  had  as  to  possible  unnecessary  expo- 
sure of  the  horns  of  the  pulp  of  the  tooth.  In  very  deep  cavities 
it  may  be  best  not  to  square  up  the  whole  central  depth  of  the 
ca\ity,  because  of  danger  to  the  horns  of  the  pulp,  but  to  cut  a 
shelf,  so  to  speak,  around  the  periphery  to  form  the  principal 
seat  of  the  filling,  leaving  the  central  part  of  the  cavity  deeper. 
This  deeper  portion  should  then  be  freed  of  softened  material 
with  the  spoon  excavators.  In  no  case  should  any  decayed 
and  softened  material  be  left  in  the  deeper  parts  of  the 
cavity.  It  is  better  to  expose  the  pulp  of  the  tooth  than  to 
leave  it  covered  only  with  softened  dentin. 

In  many  cases  the  squaring  up  of  the  surrounding  walls,  and 
flattening  of  the  pulpal  wall,  may  be  more  easily  done  with  the 
hoe  1 2-5- 1 2,  or  12-5-6,  used  with  a  scraping  motion,  than  with 
the  bur. 

When  the  walls  of  the  cavity  have  been  squared  up,  and  the 
angles  of  the  pulpal  wall,  with  the  surrounding  walls,  made 
sharp  and  definite,  and  all  carious  material  removed,  the  enamel 
walls  may  be  planed  to  form,  and  made  smooth  in  every  part. 
Unless  the  enamel  walls  approach  very  close  to  the  marginal 
ridges,  they  may  be  in  the  same  plane  with  the  dentin  walls,  or 
parallel  to  the  long  axis  of  the  tooth.  But  if  they  do  approach 
closely  to  the  marginal  ridges,  the  enamel  rods  will  be  inclined 
toward  the  ridges,  and  the  enamel  wall  must  be  similarly  inclined 
to  be  in  correct  form.  This  may  always  be  discovered  by  noting 
carefully  the  direction  of  the  cleavage  of  the  enamel  while  chip- 
ping it  away,  and  the  inclination  of  the  enamel  wall  should  be 
made  to  correspond  with  the  enamel  cleavage.  When  the 
enamel  wall  is  in  correct  form  and  planed  smooth,  the  cavo-sur- 
face  angle  must  be  slightly  beveled  in  every  part.  This  bevel 
should  not  extend  to  more  than  one-fourth  the  thickness  of  the 
enamel,  and  often  should  be  much  less. 

Generally  such  cavities  need  no  convenience  points  for  starting 
fillings,  but  when  large,  and  the  operator  feels  that  slight  con- 
venience pits  will  aid  him,  there  is  no  special  objection  to  their 
use.     They  should  be  placed  in  the  distal  portion  of  the  cavity. 


66  THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

Parallel  walls  and  a  flat  pulpal  wall  as  a  seat,  or  a  good  strong 
peripheral  ledge  in  very  deep  cavities,  gives  perfect  anchorage. 
No  undercuts  are  required.  All  of  this  done,  the  cavity  should 
be  swept  free  of  chips  and  fine  dust  and  is  ready  for  filling.  The 
use  of  chip-blower  should  be  sufficiently  frequent  and  thorough 
to  keep  the  cavity  free  from  cuttings,  and  the  whole  field  of 
operations  cleared  of  debris  during  all  parts  of  the  operation. 

In  second  and  third  molars  some  differences  of  procedure 
and  of  instrumentation  are  necessary  on  account  of  the  differ- 
ences of  position.  Often  the  bureau  not  be  brought  into  position 
for  effective  use  in  squaring  up  the  surrounding  and  pulpal  walls, 
and  this  is  done  best  with  the  hoes  12-5-6  or  1 2-5-12,  or,  in  some 
positions,  hoe  12-5-23,  used  with  a  scraping  motion.  In  a  few 
cases  the  bur  may  be  used  effectively  in  the  right-angle  hand- 
piece, but  this  is  an  awkward,  and  generally  ineffective,  instru- 
ment, and  its  use  instead  of  hand  instruments  should  be  reserved 
for  cases  of  the  greatest  necessity. 

The  mesial  wall,  and  especially  the  mesio-buccal  angle 
of  occlusal  cavities  in  the  second  and  third  molars,  should  be  so 
inclined  to  the  mesial  and  buccal  as  to  allow  of  packing  gold 
against  them  easily.  The  amount  of  this  inclination  will  depend 
upon  the  position  and  the  character  of  the  approach  to  the 
cavity.  If  the  mouth  of  the  patient  opens  well,  giving  a  good 
view,  and  allows  instruments  to  be  placed  very  nearly  parallel 
with  the  long  axis  of  the  tooth  operated  upon,  very  little  inclina- 
tion to  the  mesial  and  buccal  will  be  required.  If,  on  the  other 
hand,  the  mouth  does  not  open  well,  and  the  approach  of  the 
instruments  must  be  at  a  considerable  inclination  to  the  distal, 
the  mesial  wall  and  the  mesio-buccal  angle  must  be  inclined  in 
proportion,  or  sufficiently  to  allow  of  mallet  force  being  applied 
parallel  with  the  plane  of  this  wall  and  angle.  Any  failure  in  this 
will  require  in  filling  with  gold  that  the  gold  be  packed  against 
this  wall  by  lateral  hand-pressure,  which  greatly  increases  the 
difficulty  of  making  a  good  filling.  When  the  preparation  is  for 
amalgam  fillings  this  is  not  demanded,  but  it  is  still  desirable. 

When  the  distal  pit  in  the  occlusal  surface  of  the  upper 
molars  is  the  seat  of  operation,  the  procedure  is  not  essentially 
different,  except  that  the  approach  should  be  rather  more  from 
the  buccal.  The  same  instruments  and  the  same  methods  should 
be  employed.     In  these  it  is  very  generally  necessary  to  cut  out 


EXCAVATION    OF    CAVITIES    BY    CLASSES.  67 

the  disto-lingual  groove  to  the  crest  of  the  hngual  marginal  ridge, 
and  frequently  to  follow  it  over  onto  the  lingual  surface  of  the 
tooth.  This  should  be  done  with  the  inverted  cone  bur,  as 
previously  described  (pages  35  and  62). 

In  the  lower  molars  the  grooves  are  generally  deeper  and 
more  deeply  sulcate  than  in  the  uppers,  and  will  much  oftener 
require  cutting  out  to  the  crests  of  the  marginal  ridges.  These 
teeth  frequently  have  a  lingual  inclination,  which  renders  occlusal 
cavities  less  easy  of  approach.  In  this  they  present  great  varia- 
tion, many  being  as  easy  of  approach  as  the  upper  teeth,  and 
sometimes  easier.  Yet  frequently  there  occurs  a  lingual  inclina- 
tion that  renders  them  very  difficult.  If  these  are  prepared  for 
filling  with  gold  by  the  use  of  direct  force,  the  mesial  wall  must 
be  inclined  to  the  mesial,  and  the  mesial  portion  of  the  buccal 
wall  must  be  strongly  inclined  to  the  buccal  to  allow  of  direct 
force  being  used.  It  is  in  these  cases,  however,  that  reverse 
pluggers  have  their  greatest  use,  and  when  such  cavities  are  to 
be  prepared  for  the  use  of  these,  the  mesial  and  buccal  walls  may 
be  squared  up  in  the  axial  plane ''^  without  inclination  by  use  of 
the.  square-ended  fissure  bur  in  the  right-angle  hand-piece,  or 
with  hoes  12-5- 12  and  12-5-23,  and  the  binangle  chisels.  Gold 
can  then  be  well  packed  with  reverse  pluggers,  but  not  by  direct 
force. 

Occlusal  cavities  in  the  upper  bicuspids  are  so  easy 
and  direct  of  access,  that  little  difficulty  is  experienced  in  their 
preparation.  The  principal  points  of  instrumentation  are  the 
same  as  have  been  described. 

Occlusal  cavities  in  the  lower  bicuspids  are  difficult 
only  in  cases  of  strong  lingual  and  distal  inclination  of  these 
teeth.  In  these  cases  the  instrumentation  is  similar  to  that 
described  for  the  second  and  third  lower  molars,  except  that 
smaller  cutting  instruments  will  be  required. 

Pit  cavities  in  the  buccal  surfaces  of  the  molars. —  The 
pit  cavities  in  the  buccal  surfaces  of  the  molars  must  be  distin- 
guished sharply  from  smooth-surface  cavities  occurring  in  these 
surfaces.  The  pit  cavities  have  their  beginning  only  in  the 
buccal  pits  and  arc  primarily  in  the  occlusal  half  of  the  buccal 
surface.  .Smooth-surface  buccal  cavities  are  primarily  in  the 
gingival   half  of  the  buccal   surface  and   begin   in   the  smooth 

*  Any  plane,  one  direction  of  which  is  parallel  with  the  long  axis  of  the  tooth. 


68  THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

portion  of  the  enamel  close  to  the  gum  margin.  They  are  not 
always  very  close  to  the  gingival  margin*  of  the  buccal  sur- 
face of  the  tooth,  because  the  free  margin  of  the  gum  often, 
particularly  in  young  people,  considerably  overlaps  the  gingival 
portion  of  this  surface. 

In  these  cavities  the  principles  of  instrumentation  are  the 
same  throughout  as  that  described  for  occlusal  cavities,  except 
as  their  location  and  the  direction  of  approach  render  differences 
necessary.  Pits,  in  which  decay  has  just  begun,  should  be 
opened  with  burs  as  described  for  occlusal  surfaces.  Where 
more  decay  has  occurred,  so  as  to  allow  the  use  of  chisels,  or 
hoes  used  as  chisels,  the  opening  should  be  made  by  chipping 
away  the  enamel.  The  squaring  up  of  the  axial  and  surround- 
ing walls  and  making  the  axial  line  angles  definite,  should  be 
done  in  the  same  way  as  in  occlusal  cavities,  if  done  with  burs, 
or  if  done  with  the  hoes  and  chisels.  Sometimes  in  the  second 
molars  and  generally  in  the  third  molars  the  angle  of  approach 
will  be  such  that  the  straight  hand-piece  of  the  engine  can  not 
approach  the  cavity  at  the  correct  angle,  and  the  right-angle 
hand-piece  must  be  used,  or  what  is  usually  better,  the  work 
must  be  done  with  hoes  and  binangle  chisels.  In  finishing  the 
enamel  walls  the  case  is  different,  in  that  the  enamel  rods  will 
generally  be  found  perpendicular  to  the  surface  upon  the  central 
part,  but  inclining  toward  the  occlusal  as  the  occlusal 
margin  of  the  surface  is  approached.  Therefore  the  incli- 
nation of  the  enamel  rods,  or  the  direction  of  the  cleavage,  should 
be  closely  noted  while  chipping  away,  and  the  occlusal  enamel 
wall  finished  in  inclination  to  the  occlusal,  so  as  to  be  parallel 
with  the  line  of  the  cleavage.  If  in  any  case  it  is  found  that 
because  of  close  approach  to  the  occlusal  surface,  the  inclination 
of  the  enamel  wall  to  the  occlusal  will  render  the  filling  material 
too  thin  at  its  margin  to  have  sufficient  strength,  the  buccal 
groove  should  be  opened  over  the  crest  of  the  marginal  ridge 
and  the  filling  carried  onto  the  occlusal  surface  in  the  form  of  a 
step.  Neglect  of  this  precaution  is  causing  the  loss  of  many 
otherwise  good  fillings  in  this  position. 


*  Note.— Distinguish  carefully  between  the  terms  gum  margin  and  gingival  line, 
or  a  gingival  margin  of  a  surface  of  a  tooth.  Gum  margin  refers  to  the  position  of 
the  free  edge  of  the  gum,  while  the  gingival  line  is  the  line  of  junction  of  the  enamel 
with  the  cementum,  or  the  normal  line  of  the  attachment  of  the  gums  to  the  tooth.  The 
gingival  margin  of  a  surface  of  a  tooth  is  at  its  gingival  line. 


EXCAVATION    OF    CAVITIES    BY    CLASSES.  69 

Pit  or  fissure  cavities  on  lingual  surfaces  do  not  occur 
in  the  lower  molars,  but  do  occur  occasionally  as  independent 
cavities  in  the  lingual  grooves  of  the  upper  molars  and  rarely 
in  the  mesio-lingual  groove  of  the  upper  first  molars,  where 
there  is  a  fifth  cusp.  The  instrumentation  in  these  is  on  the 
principles  already  given  and  requires  no  special  description. 

In  pit  cavities  in  the  lingual  surfaces  of  the  incisors, 
two  points  of  special  caution  need  to  be  mentioned.  First,  the 
location  of  the  cavity  is  such  that  the  pulp  is  easily  reached,  and 
accidentally  and  unnecessarily  exposed,  unless  especial  caution 
be  observed.  The  use  of  burs  should  be  limited  strictly  to  the 
first  opening  of  pits  but  little  decayed.  Neither  inverted  cone 
nor  fissure  burs  should  be  used  in  squaring  up  the  axial  and  sur- 
rounding walls,  because  the  angle  of  approach  is  such  that  the 
sharp  angle  of  the  bur  is  presented  toward  the  pulp,  .  instead 
of  its  square  end.  This  necessarily  defeats  the  object  as  to 
squaring  up  the  axial  and  surrounding  walls,  and  rendering  the 
axial  line  angles  sharp,  and  especially  endangers  the  pulp. 
All  of  this  work  should  be  done  with  the  hoes  and  the  smaller 
chisels. 

Except  in  the  smaller  cavities,  the  direction  of  the  enamel 
rods  will  be  much  inclined  to  the  incisal  upon  the  incisal_^wall  of 
the  cavity.  This  should  be  carefully  noted  in  clipping  away  the 
enamel,  and  the  finished  enamel  wall  should  have  the  proper 
inclination  to  give  it  the  necessary  strength. 

Smooth-Surface  Cavities. 

Classes  2,  3,  4  and  5  are  all  smooth-surface  cavities.  This 
distinction  has  been  sufficiently  described  (page  7),  but  it  is  so 
important  that  it  will  be  repeated  here.  The  special  points  of 
distinction  will  also  be  further  emphasized  as  the  procedures  are 
developed. 

Class  2. —  Cavities  in  the  gingival  third  —  not  pit  cav- 
ities —  of  the  labial,  buccal,  or  lingual  surfaces  of  the 
teeth. —  Of  these  the  smooth-surface  cavities  in  the  lingual  sur- 
faces of  the  teeth  are  so  infrequent  that  a  mention  of  them  seems 
to  be  all  that  is  necessary.  Difference  in  position  calls  for  some 
differences  in  instrumentation  between  these  and  smooth-surface 
cavities  on  the  labial  and  buccal  surfaces,  but  the  principles  of 
their  preparation  are  the  same. 


70  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

Labial  cavities  in  the  incisors  and  cuspids. —  These 
cavities  occur  in  surfaces  of  the  enamel  that  are  smooth  and  per- 
fect. There  is  no  pit,  groove  or  fissure  which  serves  as  a  start- 
ing point  for  the  carious  process.  In  this  they  are  totally 
different  in  their  conditions  and  surroundings  from  the  cavities 
which  begin  in  structural  imperfections  of  the  surfaces  of  the 
teeth,  as  pits  and  fissures.  In  the  beginning  of  pit  and  fissure 
cavities,  lodgments  of  d6bris  and  fermentable  material  is  con- 
fined to  the  pit  itself ;  the  surface  of  the  tooth  immediately  sur- 
rounding the  pit  or  fissure  is  so  situated  in  relation  to  the  uses  of 
the  teeth  that  it  is  constantly  kept  clean  by  the  friction  of  masti- 
cation. Decay  never  begins  upon  clean  surfaces.  Therefore, 
there  is  no  disposition  for  decay  to  spread  upon  the  surface  of 
the  enamel,  or  to  make  a  new  beginning  in  the  immediate 
neighborhood  of  the  pit  or  fissure  ;  it  spreads  beneath  the 
enamel  only. 

In  all  smooth-surface  cavities  the  case  is  reversed.  There  is 
no  pit  or  fissure  that  holds  debris,  but  the  position  and  relation 
of  the  surrounding  parts  of  the  surface  to  the  first  starti-ng  point 
of  decay  are  such  that  it  is  not  kept  well  cleaned  by  the  fric- 
tion of  mastication  and  the  motions  of  the  tongue,  lips  and 
cheeks.  Therefore,  it  is  much  of  the  time  in  an  unclean  condi- 
tion. This  area  of  uncleanness  will  vary  indefinitely,  so  that  the 
cases  met  with  in  practice  vary  indefinitely.  The  first  beginning 
of  decay  in  these  surfaces  is  central  to  the  area  of  habitual 
uncleanness,  or  better,  central  to  the  greatest  constancy  of  the 
uncleanness.  As  this  is  close  to  the  gum  margin,  the  first  begin- 
ning of  cavities  in  labial  surfaces  is  usually  close  to  the  gum 
margin.  But  as  the  area  of  uncleanness  is  spread  upon  the  sur- 
face, so  has  the  beginning  of  decay  a  tendency  to  spread  upon 
the  surface.  For  this  reason  we  find  in  labial  and  buccal  cavities 
broad,  shallow  injuries  to  the  enamel,  very  frequently,  and  many 
instances,  when  seen  early,  in  which  the  enamel  is  broken 
through  at  a  number  of  points  near  together,  or  spread  in  a  line 
near  the  gum  margin.  An  examination  of  these  cases  show 
clearly  the  tendency  for  the  decay  to  begin  in  the  enamel  in  a 
constantly  widening  area.  Therefore,  in  preparing  this  class  of 
cavities  for  filling,  the  principle  is  established  of  so  extending  the 
cavity  outline  as  to  include  the  area  of  the  surface,  which,  under 
the   conditions   presented,    is    especially  liable    to   decay  in  the 


EXCAVATION    OF    CAVITIES    BY    CLASSES.  71 

future.  This  is  called  extension  for  prevention.  It  applies 
to  all  smooth-surface  cavities. 

Case  I. —  A  central  incisor  has  shown  sensitiveness  near  the 
gum  margin,  and  upon  passing  a  pointed  exploring  instrument 
over  it,  it  catches  at  a  number  of  points,  and  at  some  of  these 
the  point  evidently  passes  through  the  enamel  into  the  dentin. 
Examining  the  condition  of  the  surface  carefully,  the  appearance 
of  an  area  of  habitual  uncleanness  is  found  to  extend  along  the 
gum  line,  occupying  the  middle  three-fifths  of  the  surface  mesio- 
distally,  and  about  one-third  of  the  surface  gingivo-incisally. 

The  incisor  teeth  are  now  well  cleaned  and  the  rubber  dam 
adjusted  over  them,  and  the  Hatch  clamp  applied  to  this  tooth 
and  the  gingivus  forced  well  out  of  the  way.  The  surface  indi- 
cated is  well  dried  and  examined.  The  enamel  is  found  chalky, 
whitish,  with  openings  through  its  thickness  in  the  central  area  ; 
and,  extending  mesially  and  distally  in  a  crescentic  form,  there 
are  whitish  lines.  In  these  lines  an  exploring  instrument  does 
not  catch  when  passed  lightly,  but  when  a  little  force  is  used  it 
does  catch,  showing  a  degree  of  softening  of  the  enamel.  Gin- 
givally  the  line  of  injury  ceases  abruptly  at  the  border  of  the 
gums.  That  portion  of  enamel  covered  by  the  gum  is  smooth 
and  perfect. 

Procedure, —  One,  or  two,  or  three  vigorous  strokes  of 
chisel  15  breaks  up  and  removes  the  injured  and  friable  enamel 
over  the  central  area,  leaving  the  dentin  bare,  and  reveals  the 
fact  that  it  is  exceedingly  sensitive.  An  inverted  cone  bur  with 
sharp  blades,  i  ni  millimeters  in  diameter,  is  placed  with  its  end 
perpendicular  to  the  labial  surface  directly  into  the  central  decay 
and  quickly  carried  over  the  whole  surface,  extending  the  depth 
a  little  into  the  dentin  and  somewhat  enlarging  the  opening. 
The  effect  of  this  first  movement  is  to  remove  the  hypersensitive 
area  almost,  or  quite,  completely,  and  the  rest  of  the  excavation 
can  proceed  with  much  less  pain.  The  same  bur  is  again  intro- 
duced and  carried  along  the  mark  indicating  the  position  of  the 
gum  line  until  the  mesial  border  of  the  surface  is  nearly  reached 
and  all  of  the  whitish  line  of  the  enamel  removed.  This  may 
possibly  have  required  two  or  three  cuts,  but  often  may  be  done 
with  one.  With  the  same  bur  the  distal  part  is  cut  out  the  same 
way  and  to  the  same  extent.  The  result  is  a  narrow,  crescent- 
shajjed  cavity,    no  wider  than  the  bur,  following  the  gum  line 


72  THE    TECHNICAL    PROCEDURES   IN    FILLING   TEETH. 

from  angle  to  angle  (nearly  - —  not  passing  around  quite  to  the 
actual  line  of  the  mesial  or  distal  angle  of  the  tooth,  though  in 
many  cases  it  should). 

The  incisal  wall  of  this  is  now  broken  down  with  the  straight 
chisel,  and  if  still  further  extension  to  the  incisal  seems  required, 
the  bur  is  passed  around  the  incisal  wall,  cutting  away  the  dentin 
from  beneath  the  enamel,  which  is  again  chipped  away  with  the 
chisel.  This  cutting  should  be  carried  to  the  incisal  until  such 
portion  of  the  surface  as  may  seem  especially  liable  to  future 
decay  has  been  removed.  Generally,  it  is  not  necessary  to  make 
considerable  extension  in  this  direction. 

Next,  attention  is  turned  to  the  gingival  wall.  The  first  cut 
has  removed  all  injured  enamel  in  this  direction,  but  the  length 
of  the  free  gum  margin  will  allow  of  the  cavity  being  extended 
more,  without  reaching  the  gingival  line,  and  a  finish  can  be 
made  against  perfect  enamel  that  will  be  fully  covered  by  the 
gum  margin.  This  is  just  such  a  wall  as  is  most  desirable 
in  all  smooth-surface  labial  or  buccal  cavities.  Decay 
never  begins  under  a  covering  of  healthy  gum,  and  as  long  as 
the  margin  of  the  filling  is  thus  protected,  and  the  margin  well 
made,  it  is  safe;  therefore  the  enamel  is  carefully  planed  away  to 
the  proper  position  with  very  sharp  chisels  with  a  motion  along 
the  length  of  the  wall  or  from  mesial  to  distal,  and  from  distal 
to  mesial.  In  executing  this  the  thumb  and  palm  grasp  is  to  be 
preferred. 

The  dentin  wall  is  now  cut  back  with  the  same  inverted  cone 
bur  used  previously  or  with  hoe  6-2-12  or  8-3-12,  and  slightly 
undercut  in  order  that  it  may  be  retentive.  Any  corrections 
required  in  the  gingival  enamel  wall  are  now  made.  This 
should  be  inclined  strongly  to  the  gingival,  the  particular 
inclination  having  been  determined  by  observation  of  the  direc- 
tion of  the  enamel  rods  while  trimming  away  the  enamel  from 
this  surface.  The  incisal  wall  is  also  squared  up  and  the  dentin 
wall  slightly  undercut  —  about  as  an  inverted  cone  bur  placed 
with  its  flat  end  on  the  axial  wall  would  do  it.  This  is  generally 
easier  done,  however,  with  hatchet  6-2-23.  Then  the  enamel 
wall  is  finished,  .inclining  it  slightly  to  the  incisal.  Its  cavo- 
surface  angle  should  be  slightly  beveled  by  a  planing  motion 
with  a  very  sharp  chisel  carried  very  lightly  along  its  length. 
The  mesial  and  distal  angles  of  the  cavity  are  similarly  finished. 


EXCAVATION    OF    CAVITIES    BY    CLASSES.  73 

Before  filling,  the  operator  may,  if  he  thinks  it  will  be  more  con- 
venient for  starting  the  filling,  cut  two  convenience  points,  one 
in  the  axio-mesio-gingival  angle  and  one  in  the  axio-disto- 
gingival  angle.  This  should  be  done  with  the  square  end  of  an 
inverted  cone  bur,  about  A  or  A  millimeters  in  diameter,  and  be 
about  half  the  depth  of  the  head  of  the  bur.  After  forcing  the  bur 
into  the  dentin  to  this  depth  it  should  be  drawn  a  little  away  along 
the  axio-gingival  line  angle  extending  the  pit  into  a  slight  groove 
that  diminishes  and  runs  out  at  a  length  of  about  three  diameters 
of  the  bur.  This  little  extension  will  increase  the  hold  of  the 
gold  and  render  the  starting  easier  and  more  certain. 

We  now  have  a  crescent-shaped  cavity,  with  somewhat  blunt 
points,  with  a  perfectly  flat  axial  wall  that  includes  the  area  of 
the  surface  most  liable  to  decay. 

Case  2.  Left  upper  central  incisor  with  labial  decay. — 
Cavity  open  and  occupying  the  gingival  third  of  the  surface 
inciso-gingivally,  and  the  middle  three-fifths  mesio-distally. 
The  incisors  are  cleaned,  the  rubber  dam  adjusted,  the  gingivus 
pushed  well  back  with  the  Hatch  clamp,  and  the  tooth  dried. 
It  is  now  seen  that  a  line  of  injury  to  the  enamel  runs  from  the 
mesio-gingival  angle  of  the  cavity  to  a  filling  in  the  mesial 
surface,  and  another  such  line  connects  with  the  distal  surface,  in 
which  there  is  a  small  open  cavity.  The  filling  in  the  mesial 
surface  is  good  and  sufficient  except  at  its  labio-gingival  angle, 
where  slight  decay  has  begun.  These  lines  of  injury  show  as  a 
w^hitening  of  the  enamel  only,  there  being  as  yet  no  apparent 
loss  of  substance.  The  patient  is  twenty  years  old  and  suffer- 
ing badly  from  caries. 

Procedure. — All  overhanging  enamel  is  chipped  away  from 
the  incisal  portion  with  chisel  20,  using  the  thumb  and  palm 
grasp,  and  the  dentin  wall  squared  up  to  a  sufficient  depth. 
Then  with  chisel  15  the  gingival  wall  is  cut  away  to  sound 
dentin,  again  using  the  thumb  and  palm  grasp  and  cutting  from 
mesial  to  distal.  This  wall  is  found  solid  and  clean  very  close  to 
the  gingival  line,  only  a  very  slight  band  of  thin  enamel  remain- 
ing, but  it  is  sufficient  to  prevent  actual  injury  to  the  attachment 
of  the  peridental  membrane.  This  is  favorable  and  regarded  as 
important,  because  it  insures  a  healthy  free  margin  of  gum  after 
the  operation.  The  angles  are  also  cut  to  sound  dentin  with  the 
chisel.      At   the  angles  the  superficial   injury  to  the   enamel  is 


74  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

found  to  be  more  extended  than  the  decay  in  the  dentin.  An 
inverted  cone  bur,  i  miUimeter  in  diameter,  is  placed  in  the  mesio- 
gingiwil  angle  of  the  cavity  with  its  square  end  toward  the  axial 
wall,  and  entered  into  the  dentin  just  beneath  the  dento-enamel 
junction  and  carried  along  the  line  of  whitened  enamel  to  the 
point  of  connection  with  the  filling  in  the  mesial  surface.  The 
enamel  is  chipped  from  the  incisal  wall  of  this  cut  with  chisel  15 
and  the  cut  widened  by  again  passing  the  bur,  cutting  the  dentin 
toward  the  incisal.  This  portion  of  the  incisal  wall  is  now 
trimmed  smoothly  to  its  connection  with  the  incisal  wall  of  the 
original'  cavity.  The  same  bur  is  now  entered  in  a  similar 
manner  into  the  disto- gingival  angle  of  the  cavity  and  carried  to 
the  distal  along  the  line  of  the  whitened  enamel  to  the  margin 
of  the  labial  surface  and  slightly  over  onto  the  distal  surface, 
but  not  connected  with  the  distal  cavity.  This  cut  is  stopped 
at  a  point  upon  the  distal  surface  at  which  the  outline  of  the 
distal  cavity,  when  prepared,  will  cut  into  it.  This  cut  is  now 
widened  toward  the  incisal  by  chipping  the  enamel  with  the 
chisel  and  again  cutting  away  the  dentin  with  the  bur  and 
smoothly  connected  with  the  incisal  wall  of  the  original  cavity. 
This  completes  the  outline  of  the  cavity.  The  surrounding 
walls  are  clean  and  the  retention  form  partially  provided  for,  but 
the  carious  material  in  the  central  and  deeper  portions  of  the 
cavity  is  undisturbed.  It  is  still  a  question  whether  or  not  the 
pulp  will  be  found  exposed  when  this  is  removed.  The  right- 
hand  spoon  20-9-12,  used  with  the  palm  and  thumb  grasp,  is  now 
entered  under  the  distal  margin  of  the  carious  mass  and  its  edge 
swept  across  to  the  mesial,  along  the  incisal  wall,  cutting  out  the 
decayed  material.  Another  similar  cut  is  made,  directed  to  the 
gingival  half  of  the  cavity,  by  which  the  last  of  the  carious 
material  is  removed,  leaving  all  parts  of  the  cavity  clear  and 
white.  The  pulp  is  found  covered  by  sound  Ijard  dentin.  The 
edge  of  the  spoon  is  now  passed  carefully  over  the  surface  of  the 
cavity  with  a  scraping  motion,  to  be  sure  that  no  softened  material 
remains.  This  central  portion  being  deeper  than  is  desirable  to 
make  the  surrounding  walls,  it  may  be  filled  for  a  part  of  its 
depth  with  zinc  oxyphosphate  as  a  protection  to  the  pulp,  or 
better,  its  central  portion  may  be  covered  with  a  bit  of  quill  after 
the  anchorage  of  the  filling  has  been  started  and  the  gold  built 
upon  and  over  it.     The  anchorage  is  now  to  be  perfected.     The 


EXCAVATION    OF    CAVITIES    BY    CLASSES.  <0 

gingival  dentin  wall  which  was  left  inclined  to  the  gingi\al  by 
the  chisel  is  squared  up  with  hoe  12-5- 12  and  slightly  undercut 
with  hoe  S-3-12  or  6-2-12.  Then  the  enamel  wall  is  finished  to 
the  mesial  and  distal  angles  with  chisel  15,  and  the  cavo-surface 
angle  very  slightly  beveled.  A  convenience  pit  is  now  made, 
one  toward  the  mesial  and  one  toward  the  distal  in  the  gingivo- 
axial  line  angle  with  an  u>  millimeter  inverted  cone  bur,  and  each 
extended  slightly  by  grooving  toward  the  central  part  of  the 
length  of  this  line  angle.  The  incisal  dentin  wall  is  slightly 
undercut  with  an  inverted  cone  bur  held  with  its  square  end  to 
the  axial  wall  and  passed  along  from  mesial  to  distal,  or  better, 
with  hatchet  8-3-23  or  6-2-23.  The  incisal  enamel  wall  is 
finished,  being  inclined  slightly  to  the  incisal  and  its  cavo-surface 
angle  very  lightly  beveled,  the  straight  chisel  20  being  used,  and 
cuttmg  in  the  direction  of  the  length  of  the  wall,  using  the 
thumb  and  palm  grasp. 

This  cavity  as  prepared  in\oh'es  nearly  half  the  labial  surface 
inciso-gingivally,  and  the  whole  surface  mesio-distally,  the  filling 
in  the  mesial  cavity  making  a  portion  of  the  wall.  Upon  the 
distal  the  filling,  after  being  made,  will  be  cut  into  when  the 
cavity  on  the  distal  surface  is  prepared.  It  is  a  somewhat 
extreme  type  of  labial  cavity. 

Labial  cavities  in  the  upper  laterals  and  cuspids,  in  the  lower 
front  teeth,  buccal  cavities  in  the  bicuspids  and  in  the  first  molars, 
would  be  excavated  in  the  same  manner  and  with  the  same 
instruments.  The  thumb  and  palm  grasp  of  instruments  can  not 
so  frecjuently  be  used  to  advantage  in  buccal  cavities  in  bicuspids 
and  first  molars,  as  in  like  positions  in  the  anterior  teeth.  In 
the  second  and  third  molars  this  grasp  is  usually  inapplicable. 

Generally  the  inverted  cone  or  square-ended  fissure  bur  may 
be  used  with  its  shaft  at  right  angles  to  the  buccal  surfaces  as  far 
back  as  the  first  molar,  and  in  occasional  fa\orable  cases  in  the 
second  molar.  Usually  the  right-angle  hand- piece  must  be  used 
if  the  bur  is  employed  in  excavating  buccal  cavities  in  the  second 
or  third  molars.  In  most  cases,  however,  the  instrumentation  is 
e.'isier,  and  the  excaxation  is  made  quicker  by  using  chisels  and 
the  hoe  excavators.  These  may  be  effectually  assisted  by  using 
the  inverted  cfjne  bur  for  making  extensions  toward  the  mesial, 
chijjping  tlie  enamel  from  the  occlusal  wall  of  the  slot  cut,  and 
again  undermining  with  the  bur. 


76  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

The  difficult  point  in  the  preparation  of  buccal  cavities  in  the 
second  and  third  molars  occurs  when  considerable  extension  of 
the  cavity  to  the  distal  is  required.  If  the  dentin  is  hard  and 
firm,  and  the  enamel  still  strong,  it  is  difficult  to  cut  with  hand 
instruments.  This  work  is  effectively  done  by  placing  an 
inverted  cone  bur,  i\  millimeter  in  diameter,  used  in  the  right- 
angle  hand-piece,  in  the  distal  portion  of  the  cavity,  and  entering 
it  in  the  dentin  near  the  dento-enamel  junction,  and  pushing  it 
to  the  distal,  and  at  the  same  time  drawing  it  to  the  surface.  By 
repeating  this  motion  in  cut  after  cut,  the  required  extension  may 
be  made.  This  slot  is  now  extended  by  chipping  the  enamel, 
and  again  undermining  with  the  bur  as  described  for  other  posi- 
tions. This  plan  of  operating  is  not  always  available,  however. 
Often  the  clamp  must  be  used  on  the  second  molars,  always  on 
third  molars,  and  the  bow  of  the  clamp  is  in  the  way  of  the 
right-angle  hand-piece.  In  this  case,  if  burs  are  used  at  all, 
they  must  be  used  by  a  different  method.  An  A  millimeter 
inverted  cone  bur  used  in  the  straight  hand-piece,  is  placed  with 
its  end  against  the  distal  wall  of  the  cavity,  and  its  square  end 
entered  in  the  dentin  at  the  dento-enamel  junction.  Now  by 
swaying  the  hand-piece  back  and  forth,  the  bur  is  caused  to 
enter  the  dentin  to  about  the  depth  of  its  head  ;  then,  by  pres- 
sure toward  the  surface  while  withdrawing  the  bur,  it  is  made  to 
cut  the  enamel  from  its  inner  surface.  By  repeating  this  motion, 
the  enamel  may  be  cut  through  and  a  slot  formed  of  any  desired 
extension.  The  enamel  may  now  readily  be  pared  from  the 
margins  of  this  with  straight  chisels,  the  enamel  further  under- 
mined to  the  occlusal  or  to  the  gingival  by  cutting  out  dentin 
along  the  dento-enamel  junction  with  the  bur,  and  removing 
more  enamel  with  the  chisel.  In_  this  use  of  instruments  the 
axio-gingival  and  axio-buccal  line  angles,  as  made  with  the  bur, 
are  rounded  and  not  in  good  condition  to  receive  filling  mate- 
rial. This  is  remedied  by  cutting  these  to  sharp  and  definite 
angles  with  hoe  6-2-12  or  6-2-23,  by  a  scraping  motion!.  When 
the  cavity  is  broad  gingivo-occlusally,  the  size  8-3  of  tlie  hoes 
may  be  used. 

Buccal  cavities  often  extend  so  far  gingivally  that  the  gingival 
wall  is  beyond  the  gingival  line  and  the  cavo-surface  angle  is  of 
cementum  instead  of  enamel.  This  must  always  be  regarded  as 
unfortunate,  for  the  reason  that  the  attachment  of  the  gum  to 


EXCAVATION    OF    CAVITIES    BY    CLASSES.  i  t 

the  tooth  has  been  injured  and  because  of  the  increased  difficulty 
of  making  the  filling.  The  injury  to  the  attachment  of  the 
gums  is  necessarily  permanent,  and  yet,  if  the  operation  is  well 
and  smoothly  made,  a  fair  degree  of  health  of  the  gum  margin 
is  generally  maintained.  In  these  cases  it  is  best  to  remove  the 
attached  membrane  from  the  cementum  sufficiently  to  allow 
room  for  the  clamp  and  provide  additional  room  to  readily  see 
the  cavity  margin  after  the  filling  is  in  place,  in  order  that  the 
filling  may  be, finished  definitely  and  smoothly  to  the  tooth  sur- 
face. It  is  better  to  destroy  the  attachment  a  little  further  and 
secure  a  smooth  perfect  finish,  than  to  risk  imperfect  work  at  so 
important  a  point. 

Class  3. —  Cavities  in  the  proximate  surfaces  of  the 
incisors  and  cuspids,  which  do  not  involve  the  removal 
and  restoration  of  the  mesial  or  distal  angle.— In  the 
excavation  of  this  class  of  cavities  a  much  greater  range  of  forms 
of  cutting  instruments  may  be  used  effectively  than  in  other 
classes,  and  a  greater  variation  of  method  of  instrumentation  is 
consistent  with  rapid  and  thorough  operating.  In  the  work  the 
ordinaries  are  used  almost  exclusively,  the  bur  being  employed 
only  to  accomplish  a  few  special  purposes.  The  cavities  are  all 
smooth-surface  cavities  and  the  rules  of  extension  for  prevention 
are  applied  in  their  preparation. 

Case  I. —  The  left  upper  central  incisor  has  a  decay  in  its 
mesial  surface,  just  to  the  gingival  of  its  contact  point.  Appa- 
rently it  is  small,  but  a  curved  exploring  instrument  introduced 
from  the  labial  or  from  the  lingual  enters  through  the  enamel. 

Procedure. —  The  first  procedure  is  to  free  all  of  the  incisor 
teeth  of  debris  or  micro-organisms  and  gummy  material,  par- 
ticularly about  their  gingival  portion,  and  apply  the  rubber  dam. 
Dry  the  teeth  and  apply  the- Perry  separator  and  get  sufficient 
separation  to  pass  a  thin  polishing  tape  between  the  teeth. 
Then,  with  the  8-3-6  hoe  used  as  a  chisel,  begin  near  the  labial 
margin  of  the  cavity  to  break  down  the  overhanging  enamel, 
chipping  from  the  surface  into  the  cavity.  This  should  generally 
be  done  by  hand  pressure,  being  careful  to  place  the  edge  of  the 
cutting  instrument  very  near  the  margin  in  each  instance  and 
split  off  the  enamel  in  little  flakes.  In  this  cutting  the  third 
finger  should  be  very  securely  rested  upon  the  adjacent  teeth 
and  the  motions  of  the  instrument  so  closely  controlled  that  its 


78  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

edge  will  not  be  thrust  into  the  depths  of  the  cavity  and  cause 
pain.  Continue  this  cutting  until  the  enamel  is  found  supported 
by  sound  dentin,  or  until  the  cavity  of  decay  is  well  exposed. 
In  many  cases  it  will  be  best  in  this  position,  when  decay  is 
extensive,  to  leave  some  enamel  unsupported  by  dentin,  espe- 
cially when  of  about  full  strength,  rather  than  expose  so  much 
filling  material  as  the  complete  removal  of  the  enamel  would  do. 
When  this  wall  has  been  chipped  away  sufficiently,  chip  away 
the  lingual  wall  in  the  same  way  and  with  the  same  instrument, 
working  from  the  lingual.  This,  if  the  cavity  be  not  very  small, 
will  give  good  access  to  all  of  its  parts.  If  the  cavity  is  small, 
take  hatchet  8-3-12  and  introduce  its  blade  between  the  teeth 
from  the  labial,  with  the  edge  directed  to  the  gingival,  catch  the 
enamel  near  the  cavity  margin  and  chip  it  away  by  a  prying 
motion,  using  the  proximating  tooth  as  a  fulcrum,  removing  as 
much  enamel  in  this  way  as  practicable.  Only  the  thinner  por- 
tions of  weakened  enamel  margins  can  be  removed  by  this 
motion  ;  but  now  a  stronger  instrument  may  be  used,  sufficient 
room  having  been  obtained  for  its  introduction.  Generally, 
hatchet  12-5-6  or  chisel  10  may  be  introduced  against  the  labial 
enamel  wall,  with  its  edge  directed  toward  the  gingival  and  the 
enamel  wall  trimmed  away,  using  strong  hand  pressure,  and,  by 
changing  the  direction,  the  cutting  can  be  continued  along  the 
gingival  wall  to  or  past  the  labio-lingual  center  of  the  tooth. 
With  the  same  instruments  working  from  the  lingual,  the  lingual 
wall  is  next  cut  down  in  the  same  way,  to,  and  somewhat  past, 
the  linguo-gingival  angle  of  the  cavity.  For  trimming  the 
remainder  of  the  gingival  wall  hoe  12-5-6  will  be  required,  or 
the  8-3-6  if  the  cavity  is  not  opened  sufficiently  to  admit  the 
larger  instrument.  This  is  done  with  a  scraping  motion.  Fre- 
quently hatchet  12-5- 12  will  do  this  well,  working  from  the 
labial.  The  gingival  wall  should  be  cut  to  sound  dentin  and 
made  as  nearly  flat  in  the  horizontal  plane  as  practicable. 

Now,  examine  carefully  as  to  the  requirements  of  extension 
for  prevention.  In  most  cases  a  line  of  superficial  injury  to  the 
enamel  will  be  found  running  away  labially,  from  the  labio-gin- 
gival  angle  of  the  cavity  near  the  gum  line.  Another  line  of 
superficial  injury  leads  away  in  similar  fashion  from  the  linguo- 
gingival  angle.  Often,  also,  particularly  in  the  smaller  cavities, 
there  is  superficial  enamel  injury  to  the  gingival  of  the  gingival 


EXCAVATION    OF    CAVITIES    BY    CLASSES.  79 

wall.  The  cavity  must  now  be  extended  so  that  it  will  include 
all  of  these  superficial  injuries.  To  do  this,  place  a  small  inverted 
cone  bur  (I'V  or  lu  millimeter)  in  the  labio-gingival  angle,  intro- 
ducing it  from  the  lingual  in  most  cavities,  and  enter  the  dentin 
close  to  the  enamel  junction,  and  swaying  the  hand-piece  as  much 
as  the  position  will  allow,  undermine  the  enamel  in  the  direction 
of  the  line  of  superficial  injury,  sinking  it  at  first  about  the  depth 
of  the  bur  head.  Then  very  slowly  withdraw  the  bur,  pressing 
it  toward  the  labial  and  incisal,  thus  widening  the  cut  in  this 
direction.  Now,  with  the  hoe  12-5-6  or  8-3-6,  the  undermined 
enamel  may  be  chipped  away.  These  cuttings  may  be  repeated 
until  the  extension  in  this  particular  direction  seems  sufficient. 
If  now  it  is  desirable  to  extend  the  cavity  to  the  gingival,  the 
same  bur  may  be  introduced  as  before,  and  drawn  toward  the 
lingual  with  pressure  against  the  gingival  wall,  cutting  the  den- 
tin close  against  the  dento-enamel  junction,  and  the  undermined 
enamel  chipped  away  with  the  hoes  or  hatchets,  working  from 
the  labial.  In  many  cases  all  of  this  cutting  with  the  bur  can 
better  be  done  from  the  labial,  keeping  the  shaft  of  the  instru- 
ment as  nearly  as  possible  in  line  with  the  central  axis  of  the 
tooth.  After  some  cutting  in  this  way,  the  attention  should  be 
turned  to  the  linguo-gingival  angle.  To  extend  this  the  same 
bur  should  be  introduced  from  the  labial  and  its  end  entered  into 
the  dentin  at  the  dento-enamel  junction  in  the  direction  to  under- 
mine the  line  of  injured  enamel.  In  this  position  the  first  cut 
should  generally  be  made  as  near  to  the  lingual  enamel  plate  as 
is  desirable  to  cut  the  cavity,  and  the  bur  should  be  drawn  back 
with  pressure  toward  the  gingival,  extending  the  undermining  in 
that  direction.  It  is  also  generally  desirable  in  this  position  to 
again  introduce  the  bur,  and  while  drawing  it  toward  the  labial 
make  pressure  against  the  undermined  enamel,  so  as  to  weaken 
it.  Then  it  may  be  broken  away  with  hoe  8-3-12,  catching  the 
edge  of  the  instrument  on  the  surface  and  using  a  pulling  motion, 
throwing  the  chips  into  the  cavity,  or  it  may  be  cut  away  by 
using  a  scraping  motion  from  labial  to  lingual  with  hoe  12-5-12, 
or  83-12  if  the  first  is  too  broad  to  enter  the  cavity  well.  Also 
this  is  well  done  with  hatchets  12-5- 12,  or  8-3-12,  or  enamel 
hatchet  10-6- 12  working  from  the  labial.  If  still  more  extension 
to  the  gingival  is  required,  it  is  readily  done  by  passing  the 
square  end  of  the  bur  along  the  gingival  wall,  cutting  out  the 


80  THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

dentin  close  against  the  dento-enamel  junction  and  afterward 
removing  the  enamel.  In  excavating  and  extending  cavities  in 
the  proximate  surfaces  of  the  incisors  and  cuspids,  it  should  be 
noted  particularly  that  these  surfaces  are  wedge-shaped 
or  triangular,  with  the  base  of  the  triangle  at  the  gingival 
margin,  and  that  the  finished  cavity  should  have  that 
form,  with  its  labio-gingival  and  linguo-gingival  -  angles 
widely  extended  toward  the  angles  of  the  surface  de- 
cayed. The  gingival  wall  should  be  perfectly  flat  mesio-dis- 
tally  with  the  axio -gingival  line  angle  sharp.  Labio-Iingually  it 
should  be  either  straight  and  parallel  with  the  horizontal  plane 
of  the  tooth,  or  curved  with  its  convexity  to  the  incisal. 

The  incisal  angle  should  next  receive  attention.  It  often 
happens  that  decay  has  extended  along  the  dento-enamel  junc- 
tion considerably  in  this  direction.  The  enamel  should  be 
chipped  away  with  hoe  12-5- 12  or  8-3-12  until  sound  dentin  has 
been  fully  reached,  and  in  doing  this,  very  careful  attention 
should  be  given  to  the  direction  of  cleavage  with  reference  to 
the  final  inclination  of  the  finished  enamel  wall.  When  the  out- 
line form  has  been  attained,  the  incisal  angle  should  be  undercut 
for  retention.  Usually  this  should  be  done  before  looking 
specially  to  the  retention  in  other  parts  of  the  cavity,  for  the 
strength  required  of  these  will  depend  much  upon  the  strength 
of  the  incisal  retention.  The  incisal  retention  is  made  by  under- 
cutting to  the  incisal  in  the  form  of  a  groove.  The  incisal  angle 
is  first  well  rounded  and  the  dentin  cut  away  to  some  depth 
from  the  dento-enamel  junction  directly  at  right  angles  to  the 
axial  surface  of  the  tooth,  with  hoes  8-3-12  and  8-3-23,  or 
equivalent  hatchets,  using  angle  23  mostly  close  against  the 
labial  wall.  Then  hatchet  5-3-28,  or  if  that  blade  is  too  long, 
hatchet  3-2-28  is  used  for  cutting  a  groove  in  the  incisal  angle, 
and  extending  it  along  the  labio-axial  line  angle.  The  instru- 
ment is  introduced  from  the  labial,  its  edge  directed  to  the 
incisal,  and,  beginning  at  the  labio-axial  line  angle  a  little 
removed  from  the  incisal  angle,  carry  its  edge  toward  the  incisal 
and  lingual  around  the  angle,  in  part  by  a  twist  of  the  instru- 
ment. Then  it  is  placed  well  to  the  lingual  and  swept  in  the 
opposite  direction,  or  toward  the  labial,  all  the  time  cutting  close 
against  or  slightly  into  the  axial  wall.  These  motions  are 
repeated  until  the  groove  is  of  sufficient  depth.     Now,  with  the 


EXCAVATION    OF    CAVITIES    BY    CLASSES.  81 

8-3-23  hoe,  or  if  the  cavity  is  small  the  6-2-23  hoe,  introduced 
from  the  labial  and  with  its  edge  turned  to  the  labial  or  the  axial 
wall,  the  axio-labial  line  angle  is  made  sharp  and  definite  along 
the  length  of  it  well  to  the  gingival,  using  a  scraping  motion 
from  the  gingival  toward  the  incisal.  Often  the  6-2-23  hatchet 
will  do  this  as  well,  using  it  with  a  back  and  forth  scraping 
motion,  holding  the  shaft  of  the  instrument  at  right  angles  to  the 
long  axis  of  the  tooth.  The  axio-lingual  line  angle  is  now  made 
definite  throughout  its  length,  using  hoes  8-3-12  or  6-2-12  or 
the  6-2-23  near  the  incisal  angle.  This  should  be  completed  to, 
and  into  the  axio-linguo-gingival  angle.  Undercutting  at  the 
axio-linguo-gingival  angle  for  retention  will  depend  upon  the 
strength  of  the  incisal  anchorage  ;  if  this  be  good,  but  slight 
retentive  form,  just  sufficient  to  serve  in  starting  the  filling,  is 
all  that  is  needed  in  this  position.  The '  axio-labio-gingival 
angle,  which  has  been  left  sufficiently  definite  by  the  bur,  is  now 
slightly  grooved  for  a  short  distance  toward  the  incisal,  complet- 
ing the  retentive  form  by  squaring  out  with  hoe  6-2-12  or 
hatchet  6-2-23.  Any  decay  now  remaining  in  the  deeper  parts 
of  the  central  portion  of  the  cavity  is  removed  with  spoons 
10-6-12.  Or  if  the  cavity  is  large,  the  spoons  15-8-12  may 
sometimes  be  better.  The  cavity  is  now  ready  for  the  finish  of 
the  enamel  walls  and  the  cavo-surface  angles. 

The  enamel  wall  is  planed  smooth  in  every  part  and  its 
inclination  corrected.  If  the  operator  has  noted  carefully  the 
direction  of  the  cleavage  of  the  enamel  at  all  points  while  chip- 
ping it  away,  he  will  be  at  no  loss  as  to  the  correct  inclination  at 
the  different  points,  he  remembering  that  this  shall  follow  closely 
the  cleavage  lines. 

This  is  done  in  all  parts  with  the  chisels,  except  some  por- 
tions of  the  gingival  enamel  wall  and  a  short  reach  upon  the 
lingual  wall  where  it  joins  the  incisal  angle.  The  movement  of 
the  chisel  should  be  along  the  length  of  the  enamel  wall,  cutting 
very  lightly.  It  must  be  very  sharp  to  be  effective.  At  the 
labio-gingival  and  linguo-gingival  angles  the  outline  should  form 
short  curves,  no  matter  how  sharp  the  angles  of  the  dentin 
walls;  sometimes  it  is  difficult  to  plane  the  whole  length  of  the 
gingival  wall  smoothly  with  the  chisel,  especially  where  it  joins 
the  curve  at  the  linguo-gingival  angle.  Here  hatchet  12-5-6  or 
1 2-5- 1 2  answers  better;  or  occasionally  one  of  the  hoes.  These 
6 


82  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

instruments  will  also  smooth  the  lingual  portion  of  the  curve  at 
the  incisal  angle  in  many  cases.  At  the  incisal  angle,  the  incli- 
nation of  the  enamel  wall  must  generally  be  strongly  toward  the 
incisal,  especially  in  distal  cavities,  in  order  to  follow  the  length 
of  the  enamel  rods. 

When  the  trimming  is  done,  note  carefully  whether  the 
retentive  form  has  been  injured  at  any  important  point  by 
trimming  too  deeply,  and  make  such  corrections  as  may  be 
required. 

Finally  bevel  the  cavo-surface  angle  in  all  parts  of  the 
enamel  margin,  using  the  chisel  for  nearly  all  this  work.  At  a 
few  points,  especially  along  the  gingival,  the  hatchet  12-5-6  or 
12-5-12,  or  the  10-6-12  enamel  hatchet,  will  do  the  work  easier. 
Make  the  toilet  of  the  cavity  and  fill. 

General  observations  on  the  preparation  of  prox- 
imate cavities  in  the  incisors  and  cuspids. —  In  all  cases 
the  enamel  margins  should  be  cut  sufficiently  around  the 
curves  of  the  surface  toward  the  labial  and  lingual,  that  the 
margin  will  be  well  away  from  the  contact  of  the  two  teeth 
when  the  filling  has  been  finished.  At  the  gingival  the  mar- 
gin should  be  well  covered  by  the  gum  septum  when  this  is 
in  its  normal  position.  The  gum  septum  should  be  carefully 
preserved  from  injury  in  all  parts  of  the  operation,  for  upon  the 
health  of  this  tissue  depends  largely  the  health  and  good  appear- 
ance of  the  tooth.  Toward  the  incisal  the  cutting  should 
always  include  the  normal  contact  point  in  distal  cavities.  In 
mesial  surfaces  the  contact  point  is  sometimes  so  near  the  incisal 
angle  that  this  is  impracticable.  In  these  cases,  unless  strictly 
required  by  the  extension  of  decay,  the  original  contact  point 
of  the  enamel  should  not  be  removed,  but  a  new  contact  should  be 
made  by  a  slight  fullness  of  the  filling  a  little  to  the  gingival  of  the 
position  of  the  original  contact,  so  that  the  incisal  enamel  mar- 
gin will  be  held  a  little  apart  from  contact  with  the  proximating 
tooth.  A  very  little  space  at  this  point  is  sufiicient,  for  the  rea- 
son that  to  the  incisal  of  the  contact,  in  the  use  of  the  teeth,  the 
excursions  of  food  constantly  cleans  the  margin  of  the  filling. 

In  medium  and  large  cavities  it  is  best  to  cut  the  labial  wall 
well  over  onto  the  labial  surface  of  the  tooth,  for  the  reason  that, 
if  cut  only  to  the  mesio-labial  or  disto-labial  angle  the  light  will 
not  reflect  from  the  surface  of  the  filling  and  it  will  appear  as  a 


EXCAVATION    OF   CAVITIES    BY    CLASSES.  83 

dark  cavity.  A  little  further  extension  to  the  labial  relieves  this 
and  gives  the  appearance  of  a  filling.  A  little  careful  observa- 
tion of  this  point  will  prevent  mistakes  that  are  often  very 
annoying  to  sensitive  patients.  The  appearance  of  sharp  angles 
in  cavity  outlines  that  are  exposed  to  view  should  be  avoided. 
Slighdy  curved  lines  are  better  than  straight  lines.  But  the  key 
to  good  appearance  of  operations  on  the  incisors  is  perfect  tooth 
form,  including  particularly  the  full  mesio-distal  breadth  of  the 
tooth.  In  the  incisors,  and  especially  in  the  laterals,  the  labial 
embrasure  is  usually  well  rounded  out,  and  open,  because  of  the 
rounded  form  of  the  labio-mesial  and  labio-distal  angles  of  these 
teeth.  Upon  the  lingual  the  embrasures  are  very  shallow  and 
close,  because  of  the  acuteness  of  the  mesio-lingual  and  disto- 
lingual  angles  of  the  teeth,  and  the  flatness  of  the  lingual  surfaces 
from  mesial  to  distal.  For  this  reason  the  proximate  cavities  in 
these  teeth  often  begin  well  toward  the  lingual  and  burrow  much 
more  under  the  enamel  of  the  linguo-mesial  or  linguo-distal  angle 
of  the  tooth  than  toward  the  labial.  The  result  is  that  the  enamel 
to  the  lingual  is  often  undermined  and  very  thin  from  injury  of 
the  inner  half  of  its  thickness  from  backward  decay,  or  decay  of 
its  inner  surface.  Also  the  lingual  marginal  ridges  are  often 
quite  sharp  and  the  course  of  the  enamel  rods  uncertain,  so  that 
a  good  margin  can  not  certainly  be  made  upon  the  sharp  curves 
of  these  ridges.  Therefore,  when  the  enamel  margin  of 
the  cavity  must  be  laid  against  the  enamel  of  the  lingual 
marginal  ridge,  it  is  best  to  cut  away  the  marginal  ridge 
and  lay  the  enamel  margin  of  the  cavity  on  the  lingual 
surface  of  the  tooth.  In  this  case  this  enamel  wall  will  be 
cut  parallel  with  the  axial  wall  of  the  cavity,  or  in  the  labio- 
lingual  plane  of  the  tooth.  Frequendy  this  enamel  wall  will 
be  level  with  the  axial  wall  of  the  cavity,  and  this  renders  the 
placing  of  the  filling  more  than  ordinarily  difficult.  When  the 
amount  of  tissue  will  allow,  it  is  well  to  sink  the  lingual  portion 
of  the  axial  dentin  wall  sufficiendy  to  obtain  a  slight  ledge  at  the 
lingual.  This  is  readily  done  with  a  few  strokes  of  the  6-2-12  hoe 
for  the  gingival  third,  and  with  the  6-2-23  hoe  for  the  incisal 
two-thirds  of  the  lingual  wall,  introducing  these  instruments  from 
the  labial. 

Class  4. —  Cavities   in  the   proximate  surfaces    of  the 
incisor  teeth   involving  the  loss  of  the  mesial  or  distal 


84  THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

angle,  and  its  restoration. —  In  this  class  of  cases  the  prox- 
imate cavity  is  prepared,  with  the  exception  of  its  mesial  angle, 
in  the  same  way  and  with  the  same  instruments  as  have  been 
described,  except  that  the  anchorages  in  the  labio-gingival  and 
linguo-gingival  angles  are  made  deeper  and  stronger.  That  is, 
the  axial  wall  is  cut  deeper  into  the  dentin  in  the  gingival  portion 
to  the  lingual  and  to  the  labial  than  in  its  central  area,  for  the 
purpose  of  sinking  these  anchorage  points  deeper  into  the 
substance  of  the  dentin. 

The  weak  incisal  angle  is  cut  away  to  the  labial  groove,  mesial 
or  distal,  as  the  cavity  is  to  the  mesial  or  distal.  This  groove, 
although  not  very  apparent,  is  a  weak  line  in  the  enamel  at  which 
it  most  often  breaks,  and  it  should  always  be  included  when  the 
angle  is  so  weak  as  to  require  removal.  When  this  has  been 
done,  cut  away  the  incisal  edge  of  the  middle  lobe  of  the 
tooth,  i.  e. ,  to  the  next  labial  groove  mesial  or  distal,  with  the 
corundum  stone  in  the  engine  or  with  a  small  flat  jeweler's  file, 
cutting  more  from  the  lingual  than  the  labial.  The  depth  of  this 
cutting  should  depend  upon  the  thickness  of  the  cutting  edge  of 
the  tooth.  If  the  cutting  edge  be  thick  and  already  somewhat 
worn,  very  slight  cutting  is  sufficient.  If  unworn  and  thin,  the  cut- 
ting should  be  greater.  A  small  inverted  cone  bur,  not  more  than 
I'ij  millimeter  in  diameter,  is  now  caused  to  enter  the  dentin  in  the 
proximate  cavity,  close  to  the  junction  of  the  labial  and  lingual 
enamel  plates,  and  carried,  by  a  series  of  cuts  in  which  the  bur 
is  drawn  out  at  the  incisal  edge,  along  the  length  of  the  incisal 
edge  across  the  middle  lobe,  or  as  far  as  the  incisal  edge  has  been 
previously  cut.  In  this  cutting  with  the  bur,  the  labial  enamel 
plate  should  be  left  complete  and  the  cutting  done  at  the  expense 
of  the  lingual  enamel  plate.  After  the  first  cut  is  completed, 
forming  a  groove,  in  which  the  bur  should  always  reach  fully 
into  the  dentin  between  the  labial  and  lingual  plates,  the  lingual 
plate  should  be  cut  away  to  very  nearly  or  quite  the  depth  of 
the  cut  by  the  bur.  Then  the  bur  should  again  be  passed  along 
the  slight  groove  left,  cutting  it  deeper,  keeping  close  to  the  lin- 
gual rather  than  the  labial  enamel  plate,  forming  a  groove  in  the 
dentin  between  the  enamel  plates.  In  making  this  groove  it  is 
an  object  to  leave  as  much  dentin  as  possible  supporting  the 
labial  enamel  plate.  The  depth  of  the  cutting  toward  the  pulp 
of  the  tooth  must  be  guided  by  the  judgment  of  the  operator, 


EXCAVATION    OF    CAVITIES    BY    CLASSES.  85 

care  being  taken  not  to  expose  the  pulp.  But  in  these  cases  it 
is  ahvays  better  to  expose  and  remo\e  the  pulp,  than  to  fill  with 
an  anchorage  that  is  manifestly  insufficient.  The  groove  is  the 
principal  dependence  for  the  incisal  anchorage.  This  should  be 
squared  out  with  a  fissure  bur  and  its  walls  made  parallel.  No 
undercuts  or  pits  are  needed.  A  little  broadening  and  rounding 
away  where  it  joins  the  proximate  cavity  will  make  this  connec- 
tion stronger.  In  the  incisal  enamel  walls  formed  in  making 
this  incisal  step,  both  labial  and  lingual,  the  enamel  rods  incline 
toward  the  incisal,  and  these  walls  should  take  that  form  rather 
than  be  cut  at  right  angles  with  the  long  axis  of  the  tooth,  and 
then  the  cavo-surface  angle  must  be  slightly  beveled  ip  order  to 
give  it  greater  strength. 

Teeth  with  thin,  cutting  edges  are  very  difficult  of  manage- 
ment in  making  incisal  steps  for  the  restoration  of  a  lost  or  weak 
angle,  because  the  gold  built  on  them  is  too  thin  to  have  suffi- 
cient strength.  In  many  of  these  cases,  the  incisal  edge  of  all 
of  the  incisors,  or  only  the  centrals,  may  be  ground  away  in 
imitation  of  normal  wear,  and  the  incisal  edge  thickened  without 
injury  to  the  appearance.  In  doing  this  it  is  well  to  remember 
that  in  very  thin  teeth  the  horn  of  the  incisal  pulp  is  likely  to  be 
long  and  slender,  and  the  danger  of  exposing  them  in  cutting 
the  step  is  increased. 

In  cases  where  there  has  been  such  wear  of  the  incisal  edges 
of  the  teeth  that  the  dentin  is  exposed,  the  step  should  include 
all  of  the  exposed  dentin.  In  this  case  very  little  cutting  from 
the  lingual  enamel  plate  will  be  needed,  and  generally  none  from 
the  labial.  In  the  management  of  this  class  of  cases  it  should 
be  remembered  that  in  such  large  cavities  the  bulk  of  gold  in 
close  proximity  to  the  pulp  is  liable,  through  its  conductivity  of 
thermal  changes,  to  set  up  irritation  that  will  destroy  its  vitality. 
In  cases  in  which  there  seems  to  be  imminent  danger  of  this,  it 
is  better  to  remove  the  pulp  at  once.  It  is  also  better  to  remove 
the  pulp  at  once  than  to  run  serious  risk  of  losing  the  filling 
from  insufficient  anchorage  in  the  effort  to  save  the  pulp  alive. 

Class  5. —  Preparation  of  cavities  in  the  proximate 
surfaces  of  bicuspids  and  molars. —  The  preparation  of 
proximate  cavities  in  the  bicuspids  and  molars,  if  estimated  by 
the  comparative  number  of  failures  in  filling  teeth,  must  be 
regarded  as  the  most  difficult  of  filling  operations.     Therefore, 


86  THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

more  than  usual  attention  should  be  given  by  the  student  to  the 
specific  plans  and  details  of  these  operations.  The  instruments 
used  are  almost  exclusively  the  specials.  There  is  very  little 
that  can  be  done  advantageously  with  the  ordinaries  except 
some  occasional  cutting  with  the  larger  sizes.  More  cutting 
away  of  sound  firm  dentin  and  enamel  is  required  than  in  any 
other  class  of  cavities.  The  proximating  surfaces  are  broad,  and 
for  success  in  preventing  recurrence  of  decay,  it  is  required  that 
these  be  cut  away,  so  that  the  outlines  of  the  cavity  be  free  from 
near  contact  with  proximating  teeth,  and  laid  in  such  position 
that  they  will  be  well  cleaned  by  excursions  of  food  over  them  in 
mastication.  Also,  in  making  fillings  it  is  of  the  utmost  impor- 
tance that  the  contact  be  restored  in  normal  form  for  the  protec- 
tion of  the  interproximate  gum  septum,  that  this  may  be  retained 
in  health  and  vigor.  To  do  this  effectually,  it  is  required  that 
these  fillings  be  finished  to  the  full  mesio-distal  breadth  of  the 
teeth. 

Case. —  A  right  upper  first  molar  has  a  decay  in  its  mesial 
surface,  which  has  been  discovered  by  the  patient  because  of  a 
slight  breaking  away  of  the  mesial  marginal  ridge,  disclosing  the 
cavity.  Examination  with  the  exploring  instrument  shows  the 
cavity  to  occupy  about  half  of  the  mesial  surface  occluso-gingi- 
vally  and  the  middle  two-fourths  bucco-lingually  in  its  extension 
beneath  the  enamel,  though  the  enamel  opening  is  very  much 
smaller. 

Procedure. —  In  these  cases  it  always  becomes  a  question 
as  to  when  the  rubber  dam  and  the  Perry  separator  shall  be 
adjusted.  It  may  be  done  first,  or  it  may  be  done  after  the 
cavity  has  been  opened  and  the  outline  form  roughly  cut.  But 
it  must  always  be  done  before  the  final  shaping  and  trimming  of 
the  walls  and  margins  of  the  cavity  is  undertaken. 

Opening  the  cavity. —  With  straight  chisel  15,  preferably 
by  mallet  pressure,  though  hand  pressure  may  be  used,  begin 
chipping  away  the  mesial  marginal  ridge  of  enamel  overhanging 
the  decayed  area,  first  toward  the  buccal,  and  then  toward  the 
lingual,  and  continue  until  the  enamel  is  found  supported  by 
sound  dentin.  In  the  cutting,  especially  if  done  by  hand  pres- 
sure, the  edge  of  the  chisel  should  be  set  very  close  to  the  mar- 
gin to  be  chipped,  and  the  enamel  cleaved  off  in  little  flakes,  the 
direction  of  the  pressure  and  the  motion  being  almost  in  the  line 


EXCAVATION   OF    CAVITIES    BY    CLASSES.  »( 

of  the  length  of  the  enamel  rods,  but  slightly  inclined  in  a  direc- 
tion to  throw  the  chips  off  from  the  free  surface  into  the  cavity. 
The  instrument  must  be  very  sharp  to  be  effective.  Then  cut 
away  the  enamel  toward  the  central  fossa,  as  far  as  it  can  well  be 
done  by  the  chisel.  At  this  point  it  is  well  to  take  the  enamel 
hatchets  15-8- 12,  or  20-9-12  if  there  is  sufficient  room,  and  trim 
the  overhanging  enamel  from  the  buccal  and  lingual  walls  of  the 
cavity  with  a  few  strong,  vigorous  strokes,  or  the  buccal  wall 
may  usually  be  cut  with  the  straight  or  binangle  chisel,  using 
the  enamel  hatchet  for  the  lingual  wall.  Then  sweep  the  enamel 
hatchets  around  the  gingival  wall  with  a  scraping  motion,  cutting 
to  sound  dentin.  Note  particularly  that  the  enamel  hatchet  of 
the  right  bevel,  to  cut  the  lingual  wall, 'should  cut  to  the 
lingual  in  trimming  gingival  wall ;  while  the  one  with  the 
right  bevel,  to  cut  the  buccal  wall,  should  move  to  the  buccal 
in  cutting  the  gingival  wall.  If  the  cavity  is  shallow  mesio- 
distally,  this  will  incidentally  remove  most  of  the  carious  dentin  ; 
but  that  is  immaterial.  If  the  cavity  is  very  deep  mesio-distally, 
no  further  effort  should  now  be  made  to  remove  the  carious 
dentin.  The  outlines  of  the  cavity  are  exposed,  and  that  is 
sufficient.  The  next  procedure  is  to  cut  a  step  in  the  occlusal 
surface  for  the  retention,  and  complete  the  outline  of  the  cavity 
in  this  direction.  Select  an  inverted  cone  bur  not  more  than 
one  millimeter  in  diameter,  and  placing  its  shaft  nearly  or  quite 
parallel  with  the  long  axis  of  the  tooth,  enter  the  bur  sidewise 
into  the  dentin  just  beneath  the  dento-enamel  junction,  and 
draw  it  slowly  to  the  occlusal  surface  of  the  enamel.  Repeat 
this  motion  in  cut  after  cut,  following  the  mesial  groove  distally 
to  the  pit  in,  the  central  fossa.  Then  with  straight  chisel  15  or 
20,  or  with  the  enamel  hatchets,  chip  away  the  enamel  from 
either  side  of  the  slot  formed  by  the  bur.  Now  pass  the  bur 
along  the  slot  again,  first  pressing  it  strongly  to  the  buccal  so  as 
to  undermine  the  enamel,  then  pressing  to  the  lingual,  and  again 
chip  away  the  enamel  both  to  the  buccal  and  to  the  lingual. 
Repeat  this  until  the  step  occupies  the  full  middle  third  of  the 
occlusal  surface  bucco-lingually  to  and  including  the  pit  in  the 
central  fossa.  Now  the  buccal  groove  and  other  sharp  grooves 
should  be  cut  out  as  in  the  preparation  of  occlusal  cavities. 
This  gives  a  step  with  a  flat  pulpal  wall  and  definite  angles  with 
its  surrounding  walls,  and  of  perfect  retentive  form. 


»»  THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

Next  the  proximate  portion  of  the  cavity  must  be  extended. 
When  the  buccal  and  lingual  walls  have  been  cut  away  to 
sound  dentin,  it  is  often'  necessary  to  extend  them  further. 
They  should  be  cut  well  into  the  embrasures,  both  buccally  and 
lingually,  so  that  the  cavity  margin  will  be  removed  from  near 
contact  with  the  proximating  tooth.  When  much  sound  dentin 
must  be  removed  to  accomplish  this,  it  is  easier  to  do  it  by  intro- 
ducing an  inverted  cone  bur  into  the  dentin  against  the  dento- 
enamel  junction,  about  the  bucco-lingual  center  of  the  length  of 
the  gingival  wall,  and  carry  it  buccally  to  the  buccal  wall,  squar- 
ing out  the  bucco-^ingival  angle,  and  then,  drawing  it  along  the 
buccal  wall  toward  the  occlusal  surface,  undermine  the  enamel 
along  this  wall  also.  Then  the  undermined  enamel  is  easily 
cut  away  with  the  enamel  hatchets,  or  by  chipping  with  the 
chisel  used  from  the  buccal  angle  of  the  tooth  through  the 
embrasure.  Cut  out  and  extend  the  linguo-gingival  angle  and 
the  gingival  wall  in  the  same  way  and  using  the  same  instru- 
ments. A  good  rule  as  to  the  extent  of  the  extension  is 
to  cut  the  lingual  wall  to  a  line  where  its  margin  will  be 
in  view,  past  the  proximating  tooth  when  looking  across 
the  central  incisors  at  the  median  line,  and  make  the 
extension  of  the  buccal  wall  to  correspond.  In  some  instances 
it  will  be  found  that  after  this  extension  has  been  made,  a  line  of 
superficial  injury  to  the  enamel  extends  beyond  the  margin  of 
the  cavity  at  one  or  both  of  its  gingival  angles.  This  should  be 
carefully  looked  for,  and  when  found,  the  cavity  should  be  fur- 
ther extended  so  as  to  include  the  injured  portion. 

It  must  now  be  determined  whether  or  not  the  gingival  wall 
has  been  sufficiently  extended  gingivally  for  its  margin  and  its 
buccal  and  lingual  angles  to  be  covered  by  the  free  margin 
of  the  gums  when  the  filling  is  finished.  If  not,  it  must  be 
extended  further  to  the  gingival.  This  is  difficult  to  do  entirely 
with  hand  instruments,  but  by  using  an  inverted  cone  bur  with 
its  flat  end  against  the  gingival  wall,  it  is  inclined  sufficiently  for 
its  corner  to  engage,  and  carried,  within  the  dentin,  along  the 
dento-enamel  junction  to  the  bucco-gingival  angle,  then  inclined 
in  the  opposite  direction  it  is  carried  into  the  linguo-gingival 
angle.  In  this  way  the  enamel  to  the  gingival  is  undermined 
and  may  be  much  weakened  by  passing  the  bur  a  few  times  with 
hard  pressure  against  its  inner  side.      It  may  then  be  removed 


EXCAVATIOX   OF    CAVITIES    BY    CLASSES.  89 

with  the  enamel  hatchets  and  the  gingival  wall  be  made  horizon- 
tal and  smooth.  Its  angle  with  the  axial  wall  should  be  sharp 
and  definite. 

Any  decay  remaining  on  the  axial  wall  is  now  removed  with 
spoons  20-9-12,  or  in  this  particular  position  with  the  discoid. 
The  enamel  walls  are  now  planed  to  form.  '  In  all  of  the  occlu- 
sal portion  these  may  be  perpendicular.  On  the  buccal,  the 
enamel  wall  must  be  inclined  strongly  to  the  buccal  to  agree 
with  the  enamel  cleavage.  The  lingual  enamel  wall  must  be 
inclined  similarly  to  the  lingual.  The  inclination  given  the  buc- 
cal and  lingual  enamel  walls  will  depend  upon  their  relations  to 
the  angles  of  the  tooth.  Generally  the  plane  of  the  enamel  wall 
should  be  perpendicular  to  the  surface  of  the  tooth  at  the  partic- 
ular point  where  the  enamel  margin  is  laid.  The  apparent 
inclination  will  therefore  vary  with  its  position.  If  the  cavity 
margin  is  carried  far  around  the  angle  onto  the  buccal  surface, 
the  plane  of  the  enamel  wall  will  be  nearly  or  quite  in  the  bucco- 
lingual  plane  of  the  tooth.  If  a  less  distance,  the  inclination 
will  be  less.  The  gingival  enamel  wall  should  be  inclined  a  little 
to  the  gingival.  The  cavo-surface  angle  of  all  parts  of  the 
cavity  outline  must  now  be  beveled.  All  except  the  gingival 
and  the  rounding  of  the  bucco-and-linguo-gingival  angles  may 
be  done  with  the  chisels.  A  special  instrument  is  required  for 
beveling  the  gingival  cavo-surface  angle,  the  gingival  margin 
trimmers  20- (  80) -g- 12  for  mesial  cavities  and  20- (95) -9- 12  for  dis- 
tal cavities.  These  instruments  are  used  for  no  other  purpose 
whatever.  They  have  the  angle  of  the  edge  cut  purposely  for 
making  this  bevel.  A  few  strokes  lightly  made,  and  carried 
around  the  angle  first  with  the  right-hand  instrument  in  the  one 
direction  and  then  with  the  left-hand  instrument  in  the  other 
direction,  are  sufficient. 

The  cavity  now  only  requires  the  toilet  to  be  made^  to  be 
ready  for  filling. 

However,  most  persons  would  prefer  some  convenience  points 
in  the  gingival  portion  of  the  cavity  for  retention  in  starting  a 
gold  filling.  These  are  made,  one  in  the  axio-bucco-gingival 
angle,  and  one  in  the  axio-linguo-gingival  angle,  by  pressing  an 
inverted  cone  bur  into  the  dentin  slightly  and  drawing  it  a  short 
distance  to  the  occlusal  along  the  bucco-axial  line  angle  and  the 
axio-lingual  line  angle  respectively.     These  give  sufficient  starting 


90  THE   TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

points  and  will  retain  the  filling  while  the  building  of  this  part  is 
in  progress. 

Variations  due  to  position. — The  variations  of  procedure 
due  to  position  of  the  teeth  in  the  mouth  and  the  different 
degrees  of  exposure  of  the  parts  to  view  and  to  approach,  relate 
mostly  to  the  second  and  third  molars  and  to  the  lower  bicuspids. 
The  upper  first  bicuspids  are  usually  so  well  exposed  that  both 
the  mesial  and  distal  cavities  are  easily  reached,  and  except  that 
the  smaller  cutting  instruments,  as  the  15-8-12  and  10-6-12 
enamel  hatchets  and  corresponding  chisels  and  spoons,  are  neces- 
sary, the  instruments  and  the  instrumentation  will  be  the  same. 
Neither  is  it  often  necessary  to  make  any  variation  in  distal  cavi- 
ties in  the  first  molar  or  mesial  cavities  in  the  second  molar, 
above  or  below. 

In  distal  cavities  in  the  second  molar  and  mesial  cavities  in 
the  third  molar  it  frequently  happens  that  the  inverted  cone  bur 
can  not  be  made  to  approach  the  cavity  at  the  proper  angle  to 
square  out  and  extend  the  bucco-  and  linguo-gingival  angles.  In 
these  cases  the  bur  in  the  right-angle  hand-piece  may  be  substi- 
tuted, or  the  cutting  may  be  done  entirely  with  the  hand  instru- 
ments. However,  in  the  greater  number  of  cases  in  which  distal 
cavities  in  the  second  molar  are  excavated  at  the  same  time  with 
mesial  cavities  in  the  third,  the  straight  hand-piece  may  be  used 
for  both.  This  is  facilitated  by  cutting  the  step  in  the  second 
molar  first  and  carrying  it  well  to  the  mesial.  This  gives  addi- 
tional room  for  the  application  of  instruments  to  the  distal  portion 
of  the  cavity  and  also  to  the  mesial  cavity  in  the  third  molar. 

Occasionally  there  is  difficulty  in  so  placing  the  inverted  cone 
bur  as  to  begin  cutting  the  step  in  the  occlusal  portion  from  the 
distal  cavity  of  a  second  molar.  The  approach  is  such  that  the 
shaft  of  the  instrument  is  inclined  so  much  to  the  distal  that  the 
bur  cuts  the  enamel  from  the  surface  inward,  instead  of  cutting 
the  enamel  from  within  outward,  and  for  this  reason  will  not  cut 
well.  The  proper  position  of  the  bur  may  be  obtained  with  the 
right-angle  hand-piece,  but  if  the  enamel  proves  very  hard  this 
instrument  does  not  work  well.  It  is  better  in  such  cases  to 
enter  the  occlusal  surface  through  the  pit  in  the  central  fossa  in 
the  usual  way  of  opening  pits,  or  with  a  drill,  if  the  pit  is  fully 
closed,  and  then  enter  the  inverted  cone  bur  at  this  point  and 
cut  to  the  distal  along  the  line  of  the  distal  groove  until  the 


EXCAVATION   OF    CAVITIES    BY    CLASSES.  91 

distal  cavity  has  been  entered.  This  slot  may  then  be  broad- 
ened to  the  buccal  and  to  the  lingual  in  the  usual  way  to  form 
the  step. 

The  approach  to  distal  cavities  in  the  upper  second  molars  is 
often  somewhat  from  the  buccal,  and  to  facilitate  this  approach 
in  building  the  filling  the  buccal  wall  should  be  strongly  inclined 
to  the  buccal,  whenever  this  can  be  done  without  very  positive 
detriment  to  the  case.  One  should  never  neglect  to  obtain  such 
form  as  will  render  the  filling  of  the  cavity  convenient. 

In  the  lower  molars,  especially  those  that  have  a  strong  lin- 
gual inclination,  the  form  of  the  distal  cavity  may  be  made  for 
filling  with  reverse  pluggers.  In  this  case  the  buccal  wall  may 
be  cut  parallel  with  the  long  axis  of  the  tooth  and  the  gold 
packed  against  it  entirely  with  the  reverse  plugger. 

The  greatest  difficulty  is  met  with  in  distal  cavities  in  lower 
bicuspids  that  have  a  strong  distal  and  lingual  inclination.      It  is 
in  these  that  a  right-angle  hand-piece  and  the  reverse  pluggers 
are  most  needed.     These  teeth  are  often  small  and  the  crowns 
long  and   decayed  far  to   the  gingival.     They  are  difficult  to 
reach  with  direct  instruments.      In  these  cases  at  least  two  teeth 
to  the  distal  should  be  included  in  the  rubber  dam.     Even  if  the 
first  and  second  molars  are  lost,  the  rubber  should  include  the 
third  molar,  to  give  good  room  for  the  use  of  the  mouth  mirror, 
for  light,  and  to  hold  the  rubber  out  of  the  way  of  instruments. 
It  will  then  be  found  that  the  cavity  is  easily  reached  with  hand- 
cutting    instruments    and    the    right-angle   hand-piece,    and    is 
readily  filled  with  reverse  pluggers  after  having  attained  facility 
m  their  use.     In  the  absence  of  reverse  pluggers  much  of  the 
filling  must  be  made  by  hand  pressure.     The  form  of  the  cavity 
should  not  differ  materially  from  the  forms  produced  in  other 
teeth.      If,  however,  it  is  decided  that  direct  mallet  force  is  to  be 
employed  to  the  greatest  possible  extent,  the  disto-buccal  angle 
of  the  tooth  should  be  boldly  cut  away  sufficiently  to  give  access 
to  the  gingival  wall  and  the  greater  part  of  the  cavity  walls  gen- 
erally,  and   the  step  carried  close  against  the  mesial  marginal 
ridge.     This  will  allow  a  direct  approach  from  the  disto-buccal 
to  all  of  the  cavity  walls  except  the  axio-bucco-gingival  angle, 
which  must  be  filled  by  hand  pressure. 


92  THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

Management  of   Weak  Cavity  Walls  in    Molars    and 
Bicuspids. 

In  the  lower  molars,  especially  when  the  contacts  are  very 
broad,  the  proximate  cavities  are  likely  to  be  deepest  toward  the 
lingual,  and  to  burrow  extensively  along  the  lingual  dento- 
enamel  junction.  In  these  cases  the  lingual  wall  will  be  weak  at 
the  mesio-  or  disto-lingual  angle  of  the  tooth,  and  this  not 
infrequently  extends  to  the  central  line  of  the  lingual  surface. 
In  all  such  cases  the  removal  of  the  angle,  including  the  lingual 
cusp,  mesial  or  distal,  is  imperative.  This  should  usually  be 
done  by  catching  the  enamel  near  the  margin  of  the  cavity  with 
the  sharp  edge  of  binangle  chisel,  and  with  a  pull  toward  the 
cavity,  split  it  off.  This  may  be  thrown  off,  chip  after  chip, 
easily,  until  a  point  is  found  at  which  it  is  supported  by  sound 
dentin,  or  strong  enough  for  a  filling  to  be  built  against  it  and 
restore  .the  lost  contour  with  safety. 

In  occlusal  cavities  in  these  teeth,  the  central  pit  in  which 
decay  begins  is  much  nearer  the  lingual  than  the  buccal  surface, 
because  of  the  rounding  of  the  buccal  surface  toward  the 
occlusal.  For  this  reason  the  lingual  enamel  plate  is  often 
undermined  and  weakened  in  its  central  portion  mesio-distally, 
even  in  cavities  that  are  not  very  much  extended  in  other 
directions.  In  these  cases  the  lingual  groove  should  be  cut  out 
over  the  crest  of  the  marginal  ridge  and  the  marginal  ridge 
itself  removed  well  toward  both  the  disto-  and  mesio-lingual 
cusps.  The  gap  formed  in  the  lingual  wall  may  be  built  over 
and  the  form  of  the  tooth  restored.  In  both  these  cases  the 
enamel  wall  remaining  should  be  smoothly  cut  at  right  angles  to 
the  axial  plane  of  the  tooth. 

In  the  upper  molars  the  buccal  wall  is  more  often  the 
weak  wall.  This  does  not  so  often  occur  in  case  of  occlusal 
cavities,  though  it  is  not  infrequent.  But  often  in  mesial 
cavities  the  mesio-buccal  angle  is  found  badly  undermined  by 
decay.  If  the  decay  has  spread  along  the  dento-enamel  junction 
or  if  the  decay  has  reached  the  enamel  and  left  it  unsupported, 
the  cusp  should  be  cut  away  at  once  and  be  restored  with  the 
filling  material.  Often  in  mesial  cavities  decay  will  have 
extended  far  to  the  buccal  without  undermining  the  cusp,  in 
which  case  an  extension  of  the  enamel  margin  will  not  meet  the 


SEPARATING    TEETH.  93 

requirements  without  the  removal  of  the  cusp.      In  such  cases 
the  enamel  wall  should  be  finished  in  the  bucco-lingual  plane. 

In  upper  first  molars,  with  large  disto-lingual  cusps,  the 
contact  point  is  often  toward  the  lingual,  and  caries  of  the  distal 
surface  is  therefore  likely  to  begin  in  such  position  as  to  under- 
mine the  linguo-distal  cusp  and  weaken  the  lingual  wall  of  the 
cavity.  Also  the  disto-lingual  groove  is  usually  deep  and 
sharply  sulcate  in  these  teeth,  and  forms  a  very  weak  line  in  the 
enamel.  Therefore,  unless  the  lingual  enamel  wall  is  found  well 
supported  by  dentin,  the  cusp  should  be  removed  and  the 
enamel  cut  away  to  the  disto-lingual  groove,  and  the  cutting 
continued  toward  the  gingival  until  good  strength  is  found. 

In  the  upper  bicuspids,  the  buccal  angles  are  most  likely 
to  be  undermined  first  because  of  the  contact  point  being  well 
toward  the  buccal,  and  the  first  beginning  of  decay  occurring 
just  to  the  gingival  of  it.  When  the  angle,  either  mesial  or 
distal,  is  so  undermined  that  the  enamel  is  unsupported  by  den- 
tin, it  should  be  cut  away  to  the  buccal  groove.  This  groove, 
though  generally  so  well  closed  on  the  buccal  surfaces  of  the 
bicuspids  as  not  to  be  very  apparent,  is  still  a  weak  line  in  the 
enamel,  at  which  it  is  more  than  usually  liable  to  break. 

In  addition  to  these  special  points  of  liability  to  weak  walls, 
decay  is  liable  to  burrow  in  any  direction,  causing  weak  walls  in 
other,  and  occasionally  in  unusual,  positions.  Any  such  are  to 
be  treated  upon  the  general  lines  that  have  been  indicated.  It 
should  be  a  rule  that  when  a  wall  requires  cutting  away  be- 
cause it  has  been  weakened  by  decay,  and,  in  the  cutting,  a 
developmental  groove  is  approached,  it  should  be  cut  to,  or  past 
the  groo\'e. 

In  mesio-occluso-distal  cavities  in  the  upper  bicuspids, 
from  which  the  pulp  has  been  removed,  the  whole  of  the  occlusal 
enamel  plates  should  be  removed  to,  and  slightly  over,  their 
crests  to  the  buccal  and  lingual,  and  be  restored  by  filling 
material.  This  will  bring  the  work  of  mastication  entirely 
upon  the  filling  material  and  prevent  the  weakened  cusps  from 
being  split  off. 

Separating  Teeth. 

In  filling  proximate  cavities  in  which  the  proximate 
tooth  is  present,  provision  must  be  made  before  the  fill- 
ing is  begun  for  finishing  the  filling.     If  the  teeth  originally 


94  THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

made  a  close  contact,  it  is  necessary  to  separate  them,  or  lift 
them  a  little  apart  in  order  that  we  may  finish  the  filling  to  the 
full  mesio-distal  breadth  of  the  tooth  and  restore  the  contact  in 
correct  form,  preserving  the  full  breadth  of  the  interproximate 
space.  This  is  necessary  to  the  maintenance  of  the  health  of  the 
interproximate  gingivae,  the  gums,  the  peridental  membranes 
and  the  teeth.  If  the  contact  of  the  filling  with  the  proximating 
tooth  is  not  made  in  correct  form,  food  will  be  held  between  the 
teeth  and  will  be  crowded  upon  the  interproximate  gum  tissue, 
causing  inflammation  and  absorption,  and  finally  injure  the  gums 
and  peridental  membranes,  perhaps  causing  incurable  disease  and 
final  loss  of  the  teeth.  Or,  by  forming  a  pocket  in  the  gum 
tissue  about  the  gingival  margin  of  the  filling,  in  which  debris 
undergoes  fermentative  decomposition  with  acid  formation, 
recurrence  of  decay  is  caused  which  destroys  the  filling  and  the 
tooth.  These  considerations,  derived  from  careful  clinical  obser- 
vation, render  it  imperative  that  we  make  provision  for  finishing 
proximate  surface  fillings  to  very  exact  form  by  first  separating 
them  sufiiciently  to  give  room  to  do  this  work. 

In  all  ordinary  cases  the  separation  of  teeth  to  gain  room  for 
finishing  is  done  best  by  the  use  of  the  Perry  separator.  This  in- 
strument simply  catches  the  two  teeth  by  their  necks  and  lifts  them 
apart  by  turning  a  screw.  The  separation  required  is  done  with  the 
least  pain  possible,  is  done  at  once,  and  without  causing  especial 
soreness  of  the  teeth.  Generally  the  separator  should  be  applied 
before  the  filling  is  begun  and  the  teeth  separated  sufficiently  at 
once.  Occasionally,  and  especially  with  the  molar  teeth,  when 
the  teeth  are  very  firm,  they  are  difficult  to  move  sufficiently. 
If  in  such  cases  the  separator  is  forced  very  tight,  the  instrument 
springs  instead  of  separating  the  teeth,  B.ut  when  it  is 
allowed  to  remain  and  the  filling  is  proceeded  with,  it  is  found 
that  when  the  filling  has  been  built  and  is  ready  for  finishing  the 
continuous  spring  force  of  the  separator  has  caused  them  to  yield 
sufficiently.  "We  should  make  note  of  this  and  be  careful 
not  to  force  the  separator  too  hard  upon  the  single-rooted 
teeth,  for  if  we  attain  the  full  separation  required  at  once  we  will 
find  when  the  filling  is  completed  that  we  have  separated  the 
teeth  much  more  than  was  necessary.  All  of  this  you  will  learn 
intimately  by  observation  in  the  infirmary. 

When  the  separator  is  applied,  if  the  bows  do  not  rest  firmly 


SEPARATING    TEETH.  95 

upon  the  teeth  they  should  be  made  firm  by  propping  them  with 
gutta-percha.  To  do  this  the  gutta-percha  is  softened  by  heat 
and  placed  between  the  bows  of  the  separator  and  the  occlusal, 
or  incisal,  surfaces  of  the  teeth,  and  allow  a  little  time  for  it  to 
harden  before  finishing  the  separation.  This  should  be  done  at 
once  when  the  separator  has  been  made  just  tight  enough  to 
retain  its  position  well,  for  in  the  after  tightening  of  the  screws 
there  is  a  tendency  for  the  claws  of  the  separator  to  slip  further 
to  the  gingival  and,  coming  against  the  attachment  of  the  peri- 
dental membrane  to  the  neck  of  the  tooth,  cause  unnecessary 
pain  and  some  injury.  This  also  prevents  movements  of  the 
separator  which  causes  the  patient  much  pain  and  inconvenience 
while  operating. 

The  principal  objections  to  the  Perry  separator  are,  first,  that 
in  the  sets  of  six,  as  usually  sold,  there  are  not  a  sufficient  num- 
ber of  forms  to  accurately  fit  all  kinds  of  cases  ;  second,  that 
they  are  very  expensive  instruments  ;  and  third,  that  there  are 
many  irregular  cases  with  teeth  so  out  of  position  that  they  can 
not  be  made  to  fit.  This  last  objection  will  naturally  attach  to 
all  mechanical  devices  for  this  purpose.* 

When  the  teeth  are  very  irregular  in  the  arch,  other 
means  of  separation  often  have  to  be  devised.  Wedges  of  wood 
may  sometimes  be  used,  or  cotton  can  be  crowded  tightly  between 
the  teeth  and  tied  over  or  about  the  contact  point  with  a  ligature 
and  accomplish  a  sufficient  separation  within  a  few  days.  Drawing 
slips  of  rubber  between  the  teeth  and  cutting  the  ends  short  is  a 
very  efifective  method  of  slow  separation,  but  is  apt  to  make  the 
teeth  very  sore.  In  using  rubber  for  separating  great  care  should 
be  had  that  the  rubber  does  not  press  upon  the  gum  septum. 
This  not  only  creates  unnecessary  soreness,  but  is  liable  to  do 
great  injury  to  the  gum  septum. 

A  method  that  is  excellent  for  very  slow  separation  in  the 
molars  and  bicuspids  is  to  excavate  the  cavity  roughly  and 
moisten  its  surfaces  with  eucalyptol  to  make  the  gutta-percha 
adhere  to  the  walls,  and  then  fill  it  solidly  with  gutta-percha, 
filling  the  interproximate  space  solidly  against  the  proximating 
tooth.      In  doing  this   an   instrument  of  some   form  should  be 


NoTK.— A  modified  form  of  the  Perry  separator,  universal  in  its  application,  is  now 
under  trial,  which,  if  successful,  will  materially  reduce  the  cost,  as  one  instrument  will 
take  the  place  of  the  set  of  six. 


96  THE   TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

placed  firmly  in  the  interproximate  space  against  the  gum  septum 
while  the  gutta-percha  is  being  packed,  and  afterward  removed. 
This  will  protect  the  gum  septum  from  being  absorbed  by  the 
continued  pressure  of  the  gutta-percha.  This  point  should  never 
be  neglected,  as  a  full  gum  septum  is  necessary  to  the  health  of 
the  parts,  and  it  should  be  carefully  protected  against  injury. 
When  the  patient  is  discharged  temporarily  he  should  be  directed' 
to  make  vigorous  use  of  the  tooth  in  chewing.  The  impact  of 
the  food  will  cause  the  gutta-percha  to  spread  and  carry  the  teeth' 
apart  sufficiently  within  a  week  or  two.  This  is  a  very  effective 
method  of  slow  wedging  in  cases  in  which  the  teeth  have  dropped 
together  from  loss  of  the  contact  point,  and  has  the  merit  of 
moving  the  teeth  without  creating  soreness. 

In  cases  requiring  much  movement  it  can  be  hurried  a  great 
deal  by  first  putting  on  the  Perry  separator  and  lifting  the  teeth 
apart  as  much  as  possible,  and  making  the  gutta-percha  filling, 
as  indicated  above,  and  giving  sufficient  time  for  the  gutta- 
percha to  become  fully  hard  before  removing  the  separator. 
This  may  be  repeated  at  intervals  of  two  or  three  days  until 
sufficient  separation  has  been  obtained  to  fully  restore  the 
width  of  the  interproximate  space  and  mesio-distal  breadth  of 
the  tooth. 

It  occasionally  happens  that  a  tooth  has  lost  the  greater  part 
of  its  crown,  and  the  teeth  on  either  side  have  dropped  together 
over  it,  so  that  the  restoration  of  the  form  of  the  crown  is 
impossible  without  a  very  considerable  separation.  In  this  case 
the  breadth  of  two  interproximate  spaces  are  to  be  recovered  by 
separation.  If  the  lingual  and  buccal  walls  are  still  sufficiently 
strong,  it  is  still  possible  to  accomplish  this  with  gutta-percha, 
but  when  they  are  not  it  is  better  to  cut  away  most  of  the 
remaining  portions  of  the  crown,  and  insert  a  piece  of  hard,  dry 
hickory  wood  in  place  of  the  missing  crown  in  such  a  way  that 
the  length  of  the  grain  of  the  wood  shall  be  from  buccal  to 
lingual.  This  should  be  cut  to  fit  snugly  between  the  two  teeth 
on  either  side,  and  forced  into  position.  This  will  absorb  mois- 
ture from  the  saliva,  and  swell  and  slowly  carry  the  teeth  apart. 
The  wood  should  be  exchanged  for  a  new  piece  once  in  two  or 
three  days,  and  continued  until  space  is  gained  for  the  restora- 
tion of  the  full  mesio-distal  breadth  of  the  crown.  This  plan  is 
especially  useful  in  gaining  the  necessary  space  for  restoration 


FILLING    MATERIALS.  97 

with  artificial   crowns,  as  well  as  in   building  up  badly  decayed 
teeth  with  metal. 

Filling   Materials. 

The  fining  materials  at  present  in  use  for  permanent  opera- 
tions are,  gold,  which  holds  the  first  place,  and  amalgam,  which 
holds  a  second  place,  in  value.  Added  to  these  many  would 
reckon  tin  as  holding  a  place  equal  or  nearly  equal  to  amalgam, 
but  the. general  judgment  of  the  dental  profession  would  seem 
to  consign  tin  to  a  very  obscure  position  as  a  filling  material,  as 
nowadays  very  few  persons  make  much  use  of  it. 

The  filling  materials  for  temporary  operations  are  the  cements, 
especially  the  oxy-phosphate  of  zinc  cements,  and  gutta-percha. 

The  qualities  most  desired  in  a  filling  material  for  permanent 
operations  are  indestructibility  in  the  fluids  of  the  mouth, 
adaptability  to  the  walls  of  cavities,  freedom  from  shrinkage  or 
expansion  after  having  been  made  into  fillings,  and  resistance  to 
attrition  and  the  force  of  mastication. 

The  qualities  of  secondary  importance  are  color,  or  appear- 
ance, non-conductivity  of  the  thermal  impressions,  and  conveni- 
ence of  manipulation. 

Of  these  first  qualities  gold  seems  to  possess  in  much  the 
greatest  degree  those  most  essential.  It  is  perfecdy  indestructi- 
ble in  the  fluids  of  the  mouth;  it  is  very  perfecdy  adaptable  to 
the  walls  of  cavities;  it  is  free  from  objectionable  shrinkage  or 
expansion  ;  its  resistance  to  attrition  is  good  and  it  resists  the 
force  of  mastication  better  than  amalgam. 

Of  these  second  qualities  gold  is  not  so  good.  It  conducts 
thermal  impressions  strongly,  its  yellow  color  is  objectionable, 
and  it  is  not  very  convenient  of  manipulation.  Indeed,  it  may  be 
said  of  this  last  quality,  that  its  successful  manipulation  requires 
much  study  and  careful  experience,  and  yet,  when  this  study  is 
given  it  and  the  required  experience  has  been  obtained,  it  may 
be  worked  into  fillings  more  perfectly  than  any  other  material. 

Amalgam,  as  alloys  for  which  are  at  present  produced  by 
the  best  makers,  is  possessed  of  the  first  (jualities  in  a  high 
degree,  yet  inferior  to  gold  in  all.  It  is  not  completely  inde- 
structible in  the  fluids  of  the  mouth,  but  oxidizes  or  sulphurets 
slightly,  just  sufficient  to  change  its  color  from  a  silvery  white- 
ness to  brown  or  black.  Its  adaptability  to  the  walls  of  cavities 
7 


98  THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

is  not  SO  perfect  as  that  of  gold,  though  apparently  so  easy 
-  when  used  in  a  very  plastic  state  as  to  be  very  deceptive.  Much 
careful  study  and  experience  are  required  to  work  it  well.  Its 
resistance  to  attrition  is  good,  but  its  capability  of  resistance  to 
the  force  of  mastication  is  less  than  that  of  gold. 

Much  of  the  difficulty  attending  the  use  of  amalgam  arises 
from  a  lack  of  an  understanding  of  its  qualities.  It  is  a  metallic 
compound  in  which  each  element  entering  into  its  composition 
exerts  its  special  influence  upon  the  qualities  of  the  product;  and 
these  qualities  are  varied  with  every  little  change  in  its  composi- 
tion. These  changes  of  qualities  and  the  laws  controlling  them 
are  as  yet  understood  by  but  few  makers  of  amalgam  alloys,  and 
are  not  generally  understood  by  the  dental  profession.  For 
these  reasons  dentists  are  in  constant  danger  of  using  amalgam 
alloys  with  which  good  fillings  can  not  be  made  because  of 
shrinkage  or  expansion  of  the  material  after  being  made  into 
fillings. 

In  secondary  qualities  its  color  is  bad,  so  bad  indeed  that  it 
should  never  be  used  in  the  anterior  teeth  on  this  account.  Its 
conductivity  of  thermal  changes  is  nearly  equal  to  that  of  gold. 
Its  working  qualities  render  it  much  more  convenient  than  gold 
in  very  large  and  difficult  cavities.  It  can  be  placed  much 
quicker,  less  expenditure  of  force  is  required,  and  much  less 
time,  but  ordinarily  perfection  of  adaptation  is  less  certain. 

Forms   of   Gold. 

Gold  is  prepared  in  the  form  of  foil  for  filling  teeth.  This 
foil  is  prepared  in  various  thicknesses,  which  are  rated  on  the 
basis  of  the  number  of  grains  in  the  sheet  four  inches  square. 
If  a  sheet  of  this  size  contains  two  grains  it  is  called  No.  2;  if 
three  grains.  No.  3;  if  four  grains.  No.  4,  and  so  on  up  to  what 
is  known  as  the  heavy  foils,  such  as  Nos.  30,  60,  120,  etc. 

Gold  is  also  prepared  for  use  in  filling  teeth  in  the  crystalline 
form.  These  crystals  are  put  up  in  various  kinds  of  masses, 
with  about  as  many  names  as  there  are  makers,  and  in  these 
forms  possesses  certain  desirable  qualities,  especially  convenience 
of  manipulation.  In  any  of  these  forms,  however,  it  is  much 
less  readily  kept  in  good  working  condition  than  foil,  and  for 
this  reason  is  not  so  certain  in  its  working  properties.  It  often 
fails  to  weld  perfectly,   and  especially  it  is  often    unreliable   in 


FILLING    MATERIALS.  99 

adaptation  to  the  margins  of  cavities.  Great  effort  has  been 
made  to  bring  this  form  of  gold  into  general  use,  but  the  gen- 
eral judgment  of  the  dental  profession  has  seemed  to  be  against 
it,  for  foil  has  always  maintained  its  position  as  the  form  of 
gold  most  used. 

Welding   Properties   of  Gold. 

Gold  prepared  in  the  form  of  foil  or  crystals  welds 
perfectly  in  the  cold  state  when  clean  surfaces  are 
pressed  into  contact.  It  is  the  only  metal  which  has  this 
property  in  a  high  degree.  In  order  that  the  welding  property 
may  be  successfully  used  the  surfaces  of  the  gold  must  be 
clean.  As  this  property  of  gold  is  readily  lost  by  improper 
care,  it  is  well  to  know  intimately  the  conditions  of  the  develop- 
ment of  it,  and  the  loss  of  it. 

All  metals,  except  those  known  as  the  noble  metals,  oxidize 
quite  readily  when  exposed  to  the  air  ;  that  is,  they  attract  the 
oxygen  of  the  air  and  unite  with  it  to  form  a  film  of  oxide  upon 
the  surface.  This  prevents  the  contact  of  clean  surfaces  and 
therefore  prevents  welding.  Gold,  silver,  platinum  and  mercury 
do  not  oxidize  in  this  way,  and  it  is  for  this  reason  that  they  are 
called  noble  metals.  Silver  and  platinum  do,  however,  attract 
oxygen  to  their  surfaces  in  the  form  of  a  transparent  film  of  con- 
densed gas  sufficient  to  prevent  their  surfaces  from  coming  in 
contact,  which  prevents  them  from  welding  cold.  Gold  does  not 
attract  oxygen  nor  nitrogen  to  its  surface  and  it  is  for  this  reason 
that  it  can  be  welded  cold.  Gold  does,  however,  attract  to  its 
surface  certain  gases  that  are  often  present  in  our  atmosphere  in 
such  quantities  as  to  prevent  its  surfaces  from  coming  in  con- 
tact, and  destroy,  temporarily  or  permanently,  its  welding 
properties.  Some  of  these  gases  are  such  as  will  Ije  removed 
from  the  surface  of  the  gold  by  volatilization  when  heat  is 
applied  (by  annealing;,  rendering  the  surface  again  clean  with 
restoration  of  welding  property.  Other  gases,  notably  those  of 
the  sulphur  and  phosphorus  groups,  condense  upon  the  surface 
of  gold  and  refuse  to  volatilize  by  heat,  and  in  that  case  the 
welding  property  of  the  gold  is  permanently  destroyed.  In 
these  cases  it  seems  probable  that  compounds  in  the  form  of 
fixed  salts — non-evaporablc  —  are  formed  on  the  surface  of  the 
gold. 


100        THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

These  general  facts  with  regard  to  gold  may  readily  be  illus- 
trated by  a  few  simple  experiments,  which  any  one  can  perform. 
Ammonia  is  strongly  attracted  to  gold.  Place  a  small  quantity 
of  spirits  of  ammonia,  or  of  aqua  ammonia,  in  a  large  glass  jar. 
The  ammoniacal  gas  from  this  will  fill  the  space  above  the  liquid. 
Now  take  a  rope  of  gold  which  has  been  annealed  and  the  weld- 
ing property  of  which  is  perfect,  and  swing  it  by  a  thread  above 
the  liquid  in  the  jar  and  replace  the  cork.  In  fifteen  minutes 
remove  the  gold  and  try  its  welding  property.  It  will  not  weld 
any  more  than  so  much  tissue  paper.  If  it  is  swung  above 
chlorine  water  the  welding  property  will  be  completely  destroyed 
in  two  minutes.  Now  reanneal  these  ropes  of  gold  ;  the  welding 
property  is  completely  restored. 

How  are  we  to  know  that  this  effect  is  produced  by  a 
condensation  of  gas  on  the  surface  of  the  gold  ?  Place 
the  gold  first  in  chlorine  gas  for  ten  minutes,  and  then  transfer  it 
to  ammonia  for  an  equal  time.  Now,  as  these  two  gases  unite 
to  form  a  volatile  salt,  ammonium  chloride,  which  readily  crys- 
tallizes upon  any  cold  substance,  place  the  gold  thus  treated  in 
a  long  test  tube,  and  heat  it  quickly  over  a  bunsen  burner. 
Immediately  white  fumes  begin  to  leave  the  gold,  and  these 
crystallize  in  a  white  ring  on  the  colder  portion  of  the  test  tube. 
Chemical  examinations  of  these  crystals  show  them  to  be  ammo- 
nium chloride.  This  could  occur  only  by  the  condensation  of 
the  gases  on  tha  gold,  and  the  amount  formed  shows  this  con- 
densation to  be  in  very  considerable  quantity.  The  experiment 
may  be  varied  by  placing  the  gold  first  in  the  gaseous  ammonia, 
and  then  transferring  to  the  chlorine,  but  in  this  case  there  will 
not  be  so  large  an  amount  of  the  ammonium  chloride  formed, 
for  the  reason  that  the  ammonia  is  not  condensed  on  the  gold  in 
so  large  a  quantity  as  the  chlorine. 

In  this  experiment  the  salt  formed  is  volatile,  and  the  gold  is 
readily  cleaned  by  heat.  But  suppose  the  salt  formed  were  a 
fixed  salt  that  we  can  not  volatilize  by  the  annealing  temperature  ; 
then  the  welding  property  of  the  gold  is  permanently  destroyed. 
This  is  what  often  occurs  when  the  gold  is  not  well  protected. 
Now  one  of  the  principal  reasons  why  the  crystalline  forms  of 
gold  are  more  difficult  to  keep  in  good  condition  than  foil,  is  the 
fact  that  the  crystals  form  a  sponge  that  more  readily  takes  up 
and  holds  gases. 


FILLING    MATERIALS.  101 

By  careful  experiment  it  has  been  found  that  acid  gases  are 
most  likely  to  permanently  obscure  the  welding  property  of 
gold  ;  hence,  if  the  gold  be  kept  in  an  atmosphere  containing  a 
liberal  per  cent  of  ammonia,  ammonium  salts  will  be  formed  on 
the  gold.  These  salts  are  readily  volatile,  hence,  gold  so  kept 
will  always  be  readily  cleaned  by  annealing  and  its  welding  prop- 
erty restored. 

"We  may  use  gold,  non-cohesive  or  cohesive,  as  we 
choose,  from  the  same  book,  or  the  same  sheet,  by  sim- 
ply keeping  it  in  a  dra-wer  containing  a  small  bottle  in 
which  a  bit  of  sponge,  punk  or  cotton  is  placed  and 
occasionally  saturated  with  spirits  of  ammonia.  Used 
without  annealing  this  w^ill  be  perfectly  non-cohesive, 
or  when  annealed  will  be  perfectly  cohesive.  This 
should  be  taken  advantage  of  in  keeping  gold  in  good 
condition  for  use  in  either  form. 

Annealing  Gold. 

Gold  is  annealed  to  develop  its  welding  property. 
This  annealing  is  not  for  the  purpose  of  softening  the  metal,  as 
in  annealing  plate,  but  for  the  purpose  of  cleaning  the  surface  of 
the  gold  by  volatilizing  any  gaseous  film  that  may  have'  collected 
upon  it.  This  purpose  is  explained  sufficiently  in  the  preceding 
article.  The  best  means  of  accomplishing  this  will  depend  some- 
what upon  circumstances.  For  the  general  work  of  filling  teeth 
the  annealing  is  very  well  done  in  the  flame  of  the  alcohol  lamp 
or  the  flame  of  a  small  bunsen  burner.  The  element  of  time  is 
important  in  annealing,  particularly  if  the  annealing  is  done  at 
low  temperatures,  for  the  gases  are  not  driven  off"  at  once  unless 
a  full  red  heat  is  obtained.  Therefore,  in  annealing  in  the  flame 
the  gold  should  always  be  brought  to  a  glow,  and  so  held  for  a 
moment  or  two.  It  is  also  necessary  to  the  best  results  that 
every  particle  of  the  gold  be  brought  to  a  glow.  In  taking 
up  the  gold  with  the  pliers,  that  portion  of  it  that  is  caught 
between  the  beaks,  and  that  very  close  to  the  beaks,  will  not  be 
heated  sufficiently  to  develop  its  welding  property.  This  will 
introduce  into  the  filling  spots  of  failure  to  weld  and  greatly 
impair  the  strength  of  the  work.  For  this  reason  great  care 
should  be  exercised  in  annealing  to  see  that  all  parts  of  the  gold 
are  brought  fully  to  a  glow.     This  is  especially  important  when 


102       THE   TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

a  corner  is  to  be  built  up,  as  in  the  restoration  of  the  angle  of  an 
incisor,  or  when  a  very  solid  surface  is  to  be  made,  as  upon  the 
occlusal  surface  of  a  molar  that  will  receive  severe  wear.  Pitting 
of  the  surface  of  fillings  is  in  a  large  degree  the  result  of  the 
introduction  of  bits  of  gold  that  have  not  been  sufficiently 
annealed.  To  prevent  the  possibility  of  this  it  is  well  to  first 
anneal  one  part  and  then  lay  down  the  piece  and  catch  it  at 
another  point  and  anneal  again. 

W^hile  the  gold  should  be  heated  to  redness,  it  should 
not  be  heated  to  the  melting  point.  This  ruins  the  plasticity 
of  the  foil  and  makes  it  impossible  to  properly  condense  it.  To 
avoid  these  difficulties  the  gold  may  be  annealed  upon  a  tray  over 
the  flame  of  the  lamp.  A  number  of  devices  for  this  purpose 
can  be  had,  most  of  which  are  convenient  and  eflective.  The 
tray  may  be  made  of  metal,  of  porcelain,  or  of  mica;  it  does  not 
seem  to  make  much  difference  which  is  used.  In  annealing  in 
this  way  the  gold  may  conveniently  be  exposed  to  the  heat  for  a 
considerable  time,  and  therefore  a  full  red  heat  is  not  necessary 
to  the  complete  development  of  the  welding  property,  so  that 
there  is  no  danger  of  hardening  the  gold  by  melting  portions  of 
it.  However,  the  heat  must  closely  approach  the  point  of  red- 
ness to  be  effective.  Another  advantage  is  that  all  parts  of  the 
gold  will  become  annealed. 

The  disadvantages  of  this  method  are,  the  presence  of  such 
an  apparatus  upon  the  bracket  which  is  needed  for  operating 
instruments,  and  that  the  gold  spread  upon  the  annealing  tray 
is  liable  to  movement  by  every  motion,  or  in  the  eflbrt  to  lift 
pieces  from  it,  and  roll  together  and  stick  to  each  other  in  such 
a  way  as  to  cause  much  annoyance  and  delay  in  handling  it. 
Much  of  this  annoyance  can  be  avoided  by  having  a  tray  that 
is  so  roughened  as  to  prevent  the  rolling  or  sliding  of  the  gold. 

Filling  with  Gold. 

In  filling  teeth,  cohesive  gold  or  non-cohesive  gold  may  be 
used,  or  the  cavity  may  be  partly  filled  with  non-cohesive  gold 
and  finished  with  cohesive  gold. 

Filling  with  Non-Cohesive  Gold. 

Filling  with  non-cohesive  gold  for  the  entire  cavity  is  prac- 
ticed but  very  little  nowadays,  apparently  for  two  reasons.  It 
requires  the  development  of  a  different  order  of  skill  from  that 


FILLING    WITH    GOLD.  103 

required  for  cohesive  gold,  which  is  somewhat  difficult  to  mas- 
ter, and  it  can  not  be  used  for  contouring  or  even  in  filling  to 
form  in  cavities  that  have  lost  one  or  more  of  the  surrounding 
walls ;  for  in  this  manner  of  filling  the  principle  of  wedging  the 
gold  between  the  surrounding  walls  is  depended  upon  to  retain 
the  gold.  For  this  purpose  only  foil  is  used  and  its  lamina  must 
extend  from  the  floor  to  the  surface  of  the  cavity.  Either  the 
form  of  the  rope  or  cylinders  may  be  used.  In  this  form  of  fill- 
ing the  gold  is  not  annealed.  With  our  present  ideas  of  pre- 
paring cavities,  only  occlusal  and  buccal  or  labial  ca\  ities  that 
have  complete  and  good  surrounding  walls  would  be  suitable  for 
non-cohesive  gold  work.  The  forms  in  which  we  now  prepare 
these  are  as  suitable  for  non-cohesive  as  for  cohesive  gold,  only 
that  no  convenience  points  for  starting  the  filling  are  required 
for  non-cohesive  gold. 

In  filling  an  occlusal  ca\ity  in  a  molar  with  non-cohesive  gold 
cylinders  we  would  prepare  these  so  that  the  length  of  the  cylin- 
ders should  be  a  litde  greater  than  the  depth  of  the  cavity. 
Some  should  be  large  and  some  small,  the  size  of  the  larger  ones 
depending  upon  the  size  of  the  cavity.  Begin  with  the  cylinder 
which,  as  loosely  rolled,  would  about  fill  the  cavity  full.  Set  this 
in  the  cavity  with  one  of  its  ends  standing  upon  the  pulpal  wall 
and  the  other  protruding  from  its  orifice.  Now,  with  the  side 
of  a  large  plugger  press  the  cylinder  against  the  distal  wall.  Set 
another  cylinder  in  in  the  same  way  and  condense  it  against  the 
first.  Repeat  this  by  adding  cylinder  after  cylinder  until  the 
distal  half  or  more  of  the  cavity  is  filled.  Then  continue  by 
condensing  the  cylinders  against  the  mesial  wall,  and  in  turn  the 
buccal  and  lingual  walls,  all  the  time  using  the  lateral  pressure 
with  the  side  of  the  plugger  point,  not  with  its  end.  As  the  work 
progresses  and  the  cavity  room  is  narrowed,  the  cylinders  intro- 
duced must  be  smaller  and  smaller.  Finally,  to  obtain  room  for 
additional  cylinders,  a  sharp  point  of  a  wedge  form  must  be 
pressed  to  the  floor  of  the  cavity  and  with  a  prying  motion  the 
gold  is  wedged  against  the  cavity  walls  in  every  direction  with 
great  force.  The  space  thus  gained  is  again  filled  with  small 
cylinders  and  the  wedging  repeated  so  long  as  it  is  possible  to 
force  in  another  cylinder.  The  small  cylinders  last  introduced 
should  be  rolled  very  hard.  When  it  is  no  longer  possible  to 
force  another  cylinder  into  the  central  portion  of  the  cavity, 


104       THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

efforts  should  be  made  at  various  points  to  force  in  the  sharp, 
wedge-shaped  point  and  any  opening  made  filled  with  a  small 
cylinder.  When  no  more  gold  can  be  introduced  the  whole  sur- 
face should  be  condensed  as  completely  as  possible  with  the  end 
of  a  finely  serrated  plugger.  Then  the  surplus  gold  should  be 
trimmed  partially  and  the  condensation  repeated.  Then  again, 
trim  and  condense,  repeating  this  until  the  surface  of  the  filling 
is  brought  to  proper  form,  with  its  margins  just  flush  with  the 
cavity  margins.  Generally  these  fillings  should  be  finished  with 
the  burnisher. 

Instead  of  the  cylinders,  ropes  of  foil  may  be  used  by  carry- 
ing an  end  to  the  bottom  of  the  cavity  and  folding  in  fold  after 
fold,  so  that  one  end  of  the  loop  is  on  the  floor  of  the  cavity  and 
the  other  protruding  from  the  orifice.  These  loops  are  con- 
densed against  the  walls  laterally  and  finally  condensed  by  wedg- 
ing, the  same  way  as  in  filling  with  cylinders,  filling  the  space 
gained  by  other  loops.  The  filling  is  finished  in  a  similar 
manner. 

In  filling  buccal  or  labial  cavities  with  non-cohesive  gold  the 
steps  of  the  procedure  are  practically  the  same  as  in  filling 
occlusal  cavities.  However,  the  operation  is  generally  rather 
more  difiicult  in  these,  for  the  reason  that  the  cavities  are  so  gen- 
erally of  less  depth  in  proportion  to  their  breadth.  The  most 
convenient  cavity  to  fill  with  non-cohesive  gold  is  one  in  which 
the  depth  is  nearly  equal  to  the  breadth. 

One  who  has  become  skilful  with  this  manner  of  manipulating 
non-cohesive  gold  can  make  gold  fillings  in  cavities  suited  to  this 
work  in  much  less  time  than  they  can  be  made  with  cohesive 
gold.  This  plan  of  filling  is  often  very  desirable  for  first  molars 
for  children,  and  in  various  cases  that  come  up  in  practice  when 
it  is  important  to  shorten  the  time  of  the  operation. 

These  non-cohesive  gold  fillings  do  not  stand  attrition  so 
well  as  cohesive  gold  fillings  in  positions  where  great  wear  comes 
upon  them.  They  are,  therefore,  more  suitable  for  buccal  and 
labial  cavities.  If  very  well  done,  however,  they  do  excellent 
service  in  occlusal  cavities  where  the  wear  is  not  extraordinary. 

It  is  the  general  opinion  of  those  who  use  much  non-cohesive 
gold  that  water-tight  margins  are  more  certainly  made  with  it 
than  with  cohesive  gold.  I  am  satisfied  that  this  is  correct. 
With  the  same  care  and  skill  more  gold  can  be  put  into  a  cavity 


FILLING    WITH    GOLD.  105 

of  a  given  size,  using  non-cohesive  gold,  than  can  be  done  with 
cohesive  gold. 

The  Application  of   Force  in  Filling  with  Cohesive   Gold. 

In  using  cohesive  gold  in  filling  teeth  all  parts  of  the  gold 
should  be  welded  into  one  solid  mass.  This  is  accomplished  by 
using  the  gold  in  small  masses  and  condensing  each  of  these 
perfectly  upon  preceding  masses  with  the  end  of  the  plugger 
point,  by  either  hand  pressure  or  the  blows  of  the  mallet.  The 
use  of  hand  pressure  with  sufficient  force  to  accomplish  this 
well,  or  to  obtain  the  necessary  degree  of  solidity,  while  it  can 
readily  be  done,  becomes  exceedingly  tiresome  to  both  the 
patient  and  the  operator.  For  this  reason  mallet  force  has  come 
into  general  use.  The  kind  of  mallet  used  for  condensing  the 
gold  seems  to  be  of  much  less  importance  than  the  particular 
manner  of  handling  it,  and  this  last  must  be  stated  as  being  a 
personal  equation.  That  is  to  say,  one  person  will  accom- 
plish a  given  condensation  of  gold  with  much  less  inconvenience 
to  the  patient  than  another  can  do,  and  yet,  the  differences  in 
the  application  of  force  are  not  such  as  permit  of  analysis  and  a 
determination  of  the  precise  differences  in  manipulation. 

Of  the  different  plans  of  applying  mallet  force  the  hand  mal- 
let used  by  an  assistant  is  by  far  the  best,  as  it  will  produce  the 
desired  result  with  the  least  wear  and  tear  to  both  patient  and 
operator.  The  next  best,  but  much  inferior  method,  is  by  the 
use  of  the  automatic  mallet.  Of  these  instruments  there  are  a 
variety  in  the  market  of  almost  equal  merit.  The  poorest 
method  practiced  is  the  use  of  the  hand  mallet  by  the  operator 
himself  In  this  use  of  the  mallet  he  can  not  handle  either  the 
plugger  or  the  mallet  properly,  and  the  usual  result  is  great 
wear  and  tear  upon  both  patient  and  operator,  and  generally 
much  imperfect  work  in  condensing  the  gold,  especially  in  its 
adaptation  to  margins. 

In  order  to  condense  gold  well,  and  with  the  least  pain  to 
the  patient,  the  mallet  force  should  be  combined  with  a  certain 
degree  of  hand  pressure.  The  plugger  should  be  placed  firmly 
in  position  with  such  force  as  to  bring  the  looser  portions  of  gold 
well  together,  and  to  force  the  tooth  into  a  stable  position  in 
which  the  fibers  of  the  peridental  membrane  are  rendered  tense, 
and  then  the  blow  from  the'mallet  follows  on  the  instant  this  is 


106       THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

done.  Experience  has,  I  think,  sufficiently  shown  that  the  best 
results  are  obtained  by  this  method.  This  is  in  a  good  degree 
copied  with  the  automatic  mallets. 

The  sliding  of  the  plugger  point  over  the  surface  of  the  gold 
while  blows  are  being  rapidly  applied  is  very  much  more  painful 
to  the  patient  if  the  same  results  in  condensation  are  accom- 
plished. A  number  of  machines  for  this  kind  of  malleting  have 
been  devised  that  are  very  convenient  in  use,  and  yet  they  seem 
not  to  be  much  used,  evidently  for  the  reasons  I  have  assigned. 
It  is  perfectly  practicable,  however,  to  make  good  gold  fillings 
by  any  one  of  these  plans  of  using  mallet  force.  The  main 
questions  here  are  as  to  ease  and  rapidity  of  manipulation  in  the 
first  instance,  and,  in  the  second,  as  to  comparative  ease  of 
obtaining  good  results. 

In  most  fillings  hand  pressure  should  be  used  in  the  conden- 
sation of  some  particular  parts  to  which  mallet  force  is  inapplic- 
able. Mallet  force  can  be  applied  successfully  only  in  a  direct 
line  with  the  shaft  of  the  instrument.  In  all  cases,  in  which  it 
becomes  necessary  to  apply  force  in  lateral  directions  to  the 
shaft  of  the  instrument,  hand  pressure  must  be  used,  unless 
reverse  pluggers  can  be  substituted.  This  can  be  done  in 
the  more  difficult  positions  in  lower  molars  and  bicuspids  by 
judicious  study  of  the  capability  of  reverse  pluggers.  The  fill- 
ing of  the  incisal  anchorage  in  incisor  cavities  requires  almost 
uniformly  the  use  of  hand  pressure. 

The  manner  in  which  we  now  prepare  cavities  for  filling 
reduces  the  necessity  for  the  use  of  hand  pressure  more  than 
ever  before,  because  of  the  very  free  access  obtained.  Conven- 
ience in  placing  the  filling  material  should  always  be  held  strictly 
in  view  in  the  preparation  of  a  cavity. 

The  Relation  of  the  Size  of  Plugger  Points  to  the  Applica- 
tion of  Force. 

A  correct  appreciation  of  relation  of  the  size  of  the  condens- 
ing area  of  the  plugger  point  to  the  force  used  is  of  first  impor- 
tance in  filling  teeth  with  cohesive  gold.  The  force  that  can 
be  applied  is  limited  by  the  capability  of  the  peridental  mem- 
brane to  resist,  and  the  possibilities  of  the  use  of  more  or  less 
force  will  vary  with  the  strength  and  endurance  of  the  mem- 
brane.     People  who   have  very   strong   peridental    membranes 


FILLING    WITH    GOLD.  107 

and  are  accustomed  to  using  their  teeth  very  vigorously  in 
chewing  food,  will  bear  much  heavier  blows  of  the  mallet  than 
those  who  have  weaker  peridental  membranes  and  habitually  use 
their  teeth  more  delicately.  All  of  this  must  be  considered  in 
filling  operations  and  the  force  used  limited  accordingly.  A 
point  of  no  less  importance  is  the  requirements  as  to  solidity 
and  strength  of  fillings  for  different  persons.  Persons 
with  strong  peridental  membranes  who  use  their  teeth  vigor- 
ously require  the  strongest  possible  fillings.  Persons  who  have 
weak  peridental  membranes  and  who  habitually  use  their  teeth 
feebly  will  not  require  the  same  solidity  and  strength  in  the  fill- 
ings in  order  that  they  may  stand.  In  either  case,  however, 
the  adaptation  of  the  gold  to  the  margins  should  be  the  same, 
and  in  all  cases  a  density  that  will  be  moisture-tight  is  absolutely 
required. 

Because  a  patient  can  bear  heavy  blows  of  the  mallet 
is  no  excuse  for  using  a  plugger  of  large  impacting  area, 
for  the  reason  that  such  persons  require  very  dense 
fillings. 

For  condensing  the  main  portions  of  a  cohesive  gold  filling 
the  impacting  area  of  the  plugger  should  never  be  more  than  one 
square  millimeter,  and  generally  plugger  points  of  one-half  to 
I'a  millimeter  area  should  be  used.  The  area  of  a  plugger  point 
is  practically  the  square  of  its  diameter.  That  is,  a  point  one 
millimeter  in  diameter  has  an  area  four  times  as  great  as  one- half 
millimeter  in  diameter.  Five-tenths  multiplied  by  five-tenths 
gives  twenty-five  as  the  area,  while  ten-tenths  multiplied  by  ten- 
tenths  gives  one  hundred,  or  four  times  as  much.  This  being 
true,  a  reduction  of  the  size  of  the  plugger  point  below  one 
millimeter  increases  the  condensing  power  of  the  impact  in  pro- 
portion to  the  square  of  the  reduced  area,  and  increasing  the 
size  of  the  point  above  one  millimeter  diminishes  the  condensing 
power  of  the  impact  in  proportion  to  the  square  of  the  increased 
area.  Twenty-five  pounds  impact  or  pressure  on  a  point  one- 
half  a  millimeter  in  diameter  is  equal  in  condensing  power  to 
one  hundred  pounds  upon  a  plugger  point  one  millimeter  in 
diameter.  Therefore,  to  make  solid  fillings  small  condensing 
points  must  be  used. 

We  must  not,  however,  use  points  that  are  so  small 
that  they  will  penetrate  the  gold  and  chop  it  instead  of 


108       THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

condensing  it.  Therefore  we  should  not  use  heavy  blows  with 
very  small  plugger  points.  For  some  special  places  about  mar- 
gins, or  packing  in  delicate  grooves,  a  smaller  point  used  with 
lighter  force  is  useful.  And  occasionally  a  larger  area  than  one 
millimeter  in  the  form  of  a  foot  may  be  useful  in  packing  over 
certain  cavo-surface  angles. 

Forms  of  plugger  points. — The  form  of  the  impacting 
area  or  points  of  plugging  instruments  may  be  round,  square, 
parallelograms,  or  what  is  known  as  the  foot  forms.  All  of  these 
have  their  uses  in  special  localities.  For  the  general  work  of 
building  cohesive  gold  either  the  round,  square  or  parallelogram 
forms  may  be  used.  The  foot  forms  are  not  suited  to  general 
building  of  gold,  but  are  useful  for  condensing  over  certain  cavo- 
surface  angles  and  for  after-condensation,  especially  where  it  is 
necessary  to  reach  into  the  interproximate  space,  or  at  other  nar- 
row points  requiring  a  short  crook  of  the  plugger  point.  The 
parallelograms,  or  narrow  flat  points,  are  especially  useful  in 
condensing  gold  against  the  surrounding  walls  of  cavities 
when  the  direction  of  force  must  be  nearly  or  quite  parallel 
with  the  cavity  wall,  for  the  reason  that  they  tend  strongly  to 
wedge  the  gold  between  the  wall  and  the  condensed  gold  and 
perfect  the  adaptation  to  the  wall.  For  this  purpose  the  flat 
side  of  the  plugger  point  is  placed  parallel  with  the  wall. 

The  point  or  impacting  area  of  the  plugger  may  be  smooth 
(smooth  plugger),  or  serrated  (serrated  plugger).  Gold  fillings 
may  be  made  with  either,  but  for  general  use  the  judgment  of 
the  profession  seems  to  be  decidedly  in  favor  of  the  serrated 
point.  The  principal  object  of  the  serrations  is  to  prevent  the 
point  from  slipping  or  sliding  on  the  gold,  and  they  should  be 
just  sufficient  to  do  this  eifectively.  Long,  sharp  serrations 
should  not  be  used,  because  they  chop  into  the  gold.  ^Very 
fine,  short  serrations  are  much  the  best.  Great  care  should  be 
taken  to  keep  plugger  points  in  good  order. 

Forms  of  the  shanks  of  pluggers. — As  we  now  prepare 
cavities  with  broad,  free  access,  no  great  variety  of  crooks  and 
turns  in  the  shanks  are  necessary.  In  the  instruments  for  gen- 
eral use  a  slight  bend  in  the  shank  is  desirable  in  order  that  the 
shaft  may  be  just  a  little  out  of  the  line  of  vision.  A  perfectly 
straight  plugger  is  a  little  awkward  for  that  reason.  This  curve 
should  be  from  three  to  five  centigrades.      For  special  purposes 


FILLING    WITH    GOLD.  109 

we  need  some  special  forms  of  shank.  Especially  in  filling  upon 
the  gingival  walls  of  proximate  cavities  in  the  bicuspids  and 
molars,  a  straight  or  nearly  straight  plugger  would  necessarily 
bring  the  angle  of  force  almost  perpendicular  to  the  plane  of 
the  wall.  In  order  that  a  more  desirable  angle  of  force  may  be 
had,  a  contra-angled  shank  is  provided  that  will  reach  over  the 
proximating  tooth  and  permit  an  inclination  of  about  twelve  cen- 
tigrades  of  the  angle  of  force  toward  this  wall.  In  your  sets 
there  is  a  pair  of  these  in  parallelogram  forms  of  impacting  area 
in  which  the  width  of  blade  is  in  opposite  directions  to  the  plane 
of  the  curves  of  the  shank. 

For  filling  the  incisal  anchorages  of  incisor  cavities  an  angle 
of  twenty-five  centigrades  (a  right-angled  plugger)  is  provided 
which  is  used  entirely  by  hand  pressure.  This  instrument, 
though  used  only  for  this  one  purpose,  is  a  necessity  to  every 
outfit.  These  are,  with  the  exception  of  the  foot  pluggers,  the 
only  curves  of  shanks  required,  and  are  quite  sufficient  for  ordi- 
nary filling  operations. 

In  addition  to  these  the  school  has  provided  reverse  plug- 
gers of  several  patterns,  which  are  issued  upon  order  of  the 
demonstrators  for  use  in  some  especially  difficult  positions. 
These  are  occasionally  needful  for  certain  positions  in  filling 
lower  molars  and  bicuspids,  especially  for  packing  against  buccal 
walls  in  teeth  that  have  a  strong  lingual  inclination. 

List  of  Pluggers  Required. 

University  No.     4,     5x10-3-3  )  Face  rounded  on  dimension  lo  ; 

University  No.     5,     10x5-3-3  ^      serrated. 

University  No.     6,    4x6-5-5     I 

University  No.     7,     6x4-5-5    ^  ^^""^  ^""^  '  ^'^'''^^^'^■ 

University  No.     9,  6x12-6-10)  Contra-angled  ;  face  rounded  on 

University  No.  10,  12x6-6-10)       dimension  12;  serrated. 

University  No.  14,  5-2-23. 

No.      7,    5-10-3  I 

No.      8,    7-10-3  -  Round. 

No.      9,  10-10-3  3 

No.  322,    4x4  Bayonet  ;  serrated. 

^o-  393.    5x20.     Angle  of  face  20  ;  serrated. 

No.  408,    5x20-5-15  I 

VarneyNo.   5,   5x15-3-6  )^'°°^- 


110       THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

I  Special  Holding  Instrument. 

I  Weston's  Plugging  Assistant. 

I  Automatic  Plugger. 

Starting  cohesive  gold  fillings. — In  treating  this  subject 
I  will  suppose  that  the  cavity  has  been  prepared  as  has  been 
directed  in  the  article  on  cavity  preparation,  and  that  the  con- 
venience points  have  been  arranged  for  the  beginning  of  the 
filling.  Begin  the  filling  in  the  most  convenient  angle 
of  the  cavity.  In  occlusal  cavities  this  will  usually  be  at  some 
point  along  the  pulpo-distal  angle.  In  proximate  cavities  it  will 
usually  be  the  linguo-axio-gingival  angle.  In  buccal  cavities  it 
will  usually  be  the  axio-disto-gingival  angle.  In  labial  cavities  it 
may  be  either  the  axio-gingivo-mesial  or  the  axio-gingivo-distal 
angle,  etc. 

Select  a  plugger  point  that  will  easily  go  into  all  parts 
of  the  convenience  point  with  which  to  condense  the  first 
piece  of  gold,  and  have  the  holding  instrument  or  the  assistant 
plugger  ready  in  the  left  hand.  Select  a  piece  of  gold  rope, 
cylinder  or  block,  that  seems  rather  large  for  the  conven- 
ience point,  and  see  to  it  carefully  that  it  is  well  annealed. 
Convey  it  to  the  point  with  the  annealing  instrument  and  catch 
it  with  the  assistant  plugger  ;  hold  it  so  while  the  annealing 
instrument  is  exchanged  for  the  plugger  selected,  and  with  the 
two  bunch  the  gold  carefully  into  the  angle  and  catch  it  with  the 
assistant  plugger  in  such  a  way  that  the  condensing  instrument 
will  have  free  access  to  the  convenience  point.  Now,  condense 
the  gold  into  the  angle  by  a  few  quick  blows  of  the  mallet, 
beginning  in  the  central  portion,  and  drawing  the  outlying 
parts  of  the  gold  into  the  angle  with  the  subsequent  blows.  If 
the  convenience  point  has  been  correctly  formed  this  first  piece 
will  seldom  need  to  be  held  afterward,  but  sometimes  a  second 
and  a  third  piece  should  be  added  while  still  holding  the  gold 
with  the  assistant  plugger.  In  case  the  operator  is  using  a  hand 
mallet  with  his  own  hand  this  first  condensation  must  be  done 
by  hand  pressure.  The  first  piece  of  gold  should  always 
be  sufficient  in  quantity  so  that  the  plugger  point  will 
not  come  in  contact  with  the  dentin.  The  plugger  point 
should  never  punch  through  the  gold.  Remember  that  if  the 
bottom  of  your  convenience  point  is  round,  as  made  with  a 
round  bur,  this  first  piece  of  gold  will  roll,  but  if  the  bottom  is 


FILLING    WITH    GOLD.  Ill 

well  squared,  as  made  with  an  inverted  cone  bur,  this  first  piece 
of  gold  will  remain  firm. 

Next  proceed  to  build  up  a  mass  of  gold  upon  the  first  piece 
and  extend  this  along  one  of  the  axial  or  pulpal  angles  to  the 
second  convenience  point  and  unite  the  two.  When  this  has 
been  done  the  lodgment  of  the  gold  should  be  so  secure  that 
there  will  be  no  further  fear  of  movement  and  the  body  of  the 
filling  may  be  built  upon  this  foundation. 

If  the  case  is  an  occlusal  cavity  the  building  should  at 
first  be  about  equally  upon  the  pulpal  and  distal  walls,  forming  a 
triangular  mass  filling  the  disto-pulpal  line  angle  and  extending 
to  the  buccal  and  lingual  walls.  Later,  after  the  anchorage  has 
been  made  still  more  secure  by  some  building  across  and  across 
against  the  lingual  and  buccal  walls,  the  building  should  proceed 
more  rapidly  upon  the  pulpal  wall  until  this  is  covered  and  the 
gold  brought  securely  into  all  of  the  pulpal  line  angles. 

In  no  case  should  there  be  any  attempt  to  spread  a 
thin  layer  of  gold  on  the  pulpal  wall,  or  any  other  wall, 
of  a  cavity  and  condense  it  in  a  thin  sheet.  Any  such 
attempt  insures  a  failure  of  perfect  adaptation  to  the  wall 
of  the  cavity.  Always  secure  a  thick  mass  of  gold  along  a  line 
angle  and  build  out  on  the  wall  gradually,  keeping  the  thickened 
mass  close  to  the  margin  of  the  building  as  it  progresses  over 
the  wall  that  will  keep  the  margin  from  curling  away  from  the  wall 
as  it  is  condensed. 

The  angle  toward  the  plane  of  the  wall  at  which  the  con- 
densing force  is  applied  is  very  important  in  making  perfect 
adaptation. 

The  direction  of  force  should  never  be  perpendicular 
to  the  plane  of  the  wall  that  is  being  covered.  Whenever 
possible  the  angle  of  force  should  be  inclined  as  much  as  twelve 
centigrades  from  the  perpendicular  to  the  plane  of  the  wall.  In 
adapting  gold  to  the  surrounding  walls  in  an  occlusal  cavity  the 
direction  of  force  should  be  inclined  toward  the  wall, "if  possible, 
as  much  as  six  centigrades.  It  is  quite  possible,  by  using  the 
wedging  principle,  to  secure  good  adaptation  if  the  angle  of  force 
is  parallel  with  the  wall,  but  it  is  more  difficult. 


112       THE    TECHNICAL    PROCEDURES    IN   FILLING    TEETH. 


The   Wedging  Principle. 

The  stepping  of  the  plugger  should  always  be  from 
the  central  part  of  the  mass  of  gold  toward  the  walls, 
and  the  last  condensation  of  each  individual  piece  of 
gold  added  should  be  along  the  wall  being  covered. 

This  rule  is  practically  universal  to  filling  with  cohesive  gold, 
except  when  condensing  pieces  laid  upon  central  parts  of  the 
filling,  no  portion  of  which  is  condensed  against  a  wall  of  the 
cavity.  When  the  stepping  of  the  instrument  is  toward  the  wall, 
finishing  the  condensation  against  the  wall,  the  last  of  the 
gold  is  w^edged  betw^een  the  w^all  and  that  last  con- 
densed, thus  securing  perfect  adaptation  to  the  wall.  If,  on  the 
other  hand,  the  condensation  is  begun  at  the  wall,  the  tendency 
is  to  pull  the  gold  away  from  the  wall  in  moving  from  it  in  the 
condensation  of  the  remaining  portions,  and  to  make  imperfect 
adaptation. 

In  condensing  each  piece  of  gold  added  the  stepping  of  the 
plugger  point  should  be  in  a  regular  order,  moving  only 
the  width  of  the  condensing  point  at  each  step,  con- 
densing every  portion  of  gold.  Regular  lines  of  movement  or 
stepping  should  be  formed  generally  parallel  with  the  wall  that  is 
to  be  approached,  finishing  along  the  wall.  Such  an  order  of 
work,  pursued  with  regularity,  secures  speed  in  operating,  and 
accuracy  of  adaptation  of  the  gold  to  all  parts  of  the  cavity  walls 
and  margins. 

In  the  approach  to  and  covering  margins,  great  care  should 
be  had  not  to  step  the  instrument  onto  the  cavo-surface  angle  of 
the  cavity.  If  this  is  done  the  cavo-surface  angle  of  the  enamel 
will  be  chipped  and  rendered  imperfect.  As  the  margin  is 
approached  the  gold  should  be  laid  over  the  cavo-surface  angle 
in  sufficient  quantity  to  admit  of  malleting  directly  upon  it, 
without  danger  of  the  plugger  point  punching  through  it  and 
making  contact  with  the  enamel.  This  requires  that  the  gold  be 
built  completely  over  the  margin  at  every  point  before  the  filling 
is  regarded  as  completed. 

In  finishing  the  building  of  the  gold  to  form  there  should 
always  be  an  excess  to  allow  for  sufficient  trimming  to  remove  all 
instrument  pits  and  marks.     It  requires  much  care  and  good 


FILLING   WITH    GOLD.  113 

judgment  to  always  have  sufficient  gold  for  a  good  finish,  and 
not  have  a  wasteful  surplus. 

The   Gingival    Wall  in    Proximate  Cavities. 

The  management  of  the  gingival  wall  in  proximate  cavities, 
especially  in  the  bicuspids  and  molars,  has  always  been  the  great 
stumbling-block  in  filling  operations.  It  is  confessedly  the  most 
difficult  point  at  which  to  secure  perfect  adaptation  of  gold,  or, 
indeed,  any  other  filling  material.  In  part,  this  difficulty  has 
been  from  imperfect  preparation  of  this  wall,  but  the  real  diffi- 
culty in  securing  adaptation  lies  in  the  fact  that  the 
tendency  is  to  apply  the  condensing  force  in  a  line  per- 
pendicular to  the  plane  of  that  wall.  To  make  perfect 
adaptation  it  is  necessary  that  the  angle  of  force  be  inclined  as 
much  as  twelve  centigrades  to  the  plane  of  the  wall. 

In  mesial  cavities  in  bicuspids  and  molars  this  is  easily 
accomplished  by  using  the  contra-angled  pluggers  which  are 
made  for  this  especial  purpose.  These  instruments  will  reach 
over  the  proximating  tooth  and  give  the  correct  angle  of  force. 
The  filling  is  begun  in  the  convenience  points,  and  these  are  con- 
nected along  the  axio-gingival  angle,  as  has  been  described. 
Then  the  building  proceeds  about  equally  upon  the  axial  wall 
and  the  gingival  wall,  creeping  slowly  over  the  gingival  wall  until 
its  cavo-surface  angle  is  reached  and  has  been  built  over;  always 
keeping  a  thick  margin  of  gold  to  build  against  while  covering 
the  wall  and  cavo-surface  angle.  During  this  building  the  plane 
of  the  surface  of  gold  being  built  should  be  inclined  about  twelve 
centigrades  toward  the  long  axis  of  the  tooth,  one  margin  of  this 
plane  being  upon  the  gingival  wall,  and  the  opposite  margin 
against  the  axial  wall  in  a  direction  toward  the  occlusal  surface 
in  the  central  fossa,  if  a  molar,  and  a  similar  direction  if  a 
bicuspid. 

When  the  gingival  wall  and  its  cavo-surface  angle  has  been 
fully  covered,  then  the  building  may  be  more  rapid  in  the  prox- 
imate portion,  and  the  plane  of  the  gold  be  brought  parallel  with 
the  horizontal  plane  of  the  tooth.  The  mesial  portion  of  the 
filling  is  then  extended  to  the  mesial  to  make  the  contact  with 
the  proximating  tooth.  The  rest  of  the  filling  is  done  according 
to  rules  previously  given. 
8 


114       THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

In  distal  cavities  in  bicuspids  and  molars  it  is  more 
difficult  to  obtain  the  best  angle  of  force,  and  often  the  building 
must  proceed  differently.  The  angle  of  force  inclined  from  the 
distal  toward  the  mesial  can  not  generally  be  obtained,  and  it  is 
necessary  to  substitute  an  inclination  from  the  buccal 
toward  the  lingual.  In  the  beginning,  build  a  thick  mass  of 
gold  in  the  axio-linguo-gingival  angle,  and  gradually  extend  it 
out  to  the  cavo-surface  angle  of  the  cavity  at  that  point ;  then 
continue  the  building,  keeping  the  plane  of  the  surface  of  gold 
being  built  sloping  occluso-gingivally  from  lingual  to  buccal, 
gradually  covering  the  gingival  wall  and  its  cavo-surface  angle, 
until  the  bucco-gingival  angle  is  reached.  Then  wedge  the 
gold  into  the  bucco-gingival  angle,  between  the  gold  already 
built  and'the  buccal  wall.  After  this  is  accomplished  the  build- 
ing will  proceed  without  especial  difficulty.  In  accomplishing 
this  the  greatest  difficulties  will  be  found  in  lower  bicuspids  that 
have  a  distal  and  lingual  inclination,  and  occasionally  in  lower 
molars  that  have  a  strong  lingual  inclination.  In  these  the 
reverse  pluggers  are  a  necessity  to  easy  and  safe  w^ork. 
With  these  the  procedure  is  the  same  as  in  mesial  cavities,  except 
that  the  order  is  reversed,  as  the  left  hand  is  the  reverse  of  the 
right.  Begin  in  the  axio-bucco-gingival  angle  and  work  along  the 
axio-gingival  angle  to  the  lingual,  and  generally  fill  the  axio- 
linguo-gingival  convenience  point  with  a  direct  plugger.  After 
this  is  accomplished  the  building  is  not  difficult.  In  making  these 
fillings  entirely  with  direct  pluggers,  hand  pressure  lateral  to  the 
direction  of  the  shaft  of  the  instrument  is  often  necessary  in 
starting  the  filling,  and  in  building  over  the  gingival  cavo  sur- 
face angle,  and  also  in  much  of  the  building  against  the  buccal 
wall. 

In  proximate  cavities  in  the  incisors  and  mesial  sur- 
faces of  the  cuspids,  no  great  difficulty  will  be  found  in 
gaining  the  proper  angle  of  force  in  building  over  the  gingival 
wall  and  its  cavo-surface  angle.  These,  like  all  other  gingival 
walls  and  margins,  should  be  covered  only  after  having  secured 
a  mass  of  gold  in  the  axio-gingival  line  angle,  and  then  keeping 
the  plane  of  the  surface  of  gold  being  built  sloped  at  an  angle  of 
about  twelve  centigrades  to  the  long  axis  of  the  tooth  until  the 
gingival  wall  and  its  cavo-surface  angle  are  covered. 


FILLING   WITH    GOLD.  115 

Combination     of     Non-Cohesive     and     Cohesive    Gold     in 
Proximate  Cavities  in  the  Bicuspids  and  Molars. 

Combinations  of  non-cohesive  and  cohesive  gold  may  be  used 
effectively  in  many  positions  in  filling  teeth,  but  I  attach  great 
importance  to  it  only  in  the  gingival  portion  of  proximate  cavities 
in  the  bicuspids  and  molars.  The  best  cohesive  gold  workers 
fail,  when  they  do  fail,  oftenest  at  this  point.  And  so  difficult  is 
it  to  make  perfect  adaptation  of  cohesive  gold  to  this  wall  that 
my  observation  teaches  me  that  our  very  best  men  fail  in  ten  per 
cent  of  their  cases.  A  much  larger  per  cent  of  success  can  be 
obtained  by  the  combination  of  non-cohesive  foil,  with  a  saving 
of  both  time  and  labor.  This  is  sufficient  reason  why  I  should 
urge  this  plan  of  filling.  It  is  not,  however,  an  easy  matter  to 
learn  this  method.  It  will  not  be  gained  without  careful  study 
and  effort  in  practice. 

This  combination  consists  of  laying  a  large  flat  cylinder 
or  mat  of  non-cohesive  foil  on  the  gingival  wall  and  then 
beginning  upon  this  to  build  cohesive  gold. 

The  beginning  and  continuation  of  the  building  with  cohesive 
gold  is  the  same  in  every  respect  as  if  the  non-cohesive  gold  had 
not  been  used,  except  that  it  will  be  necessary  to  continue  the 
use  of  the  assistant  plugger  for  a  longer  time  before  the  mass  is 
perfectly  secure  in  its  position. 

The  flat  cylinder  or  mat  is  made  by  first  folding  a  sheet  foil, 
or  such  part  of  a  sheet  as  may  be  required,  to  the  right  width, 
and  then  rolling  the  ribbon  formed  upon  a  flat  steel  instrument 
of  suitable  width.  The  length  of  the  cylinder  is  controlled  by 
the  width  of  the  ribbon,  and  the  breadth  is  controlled  by  the 
width  of  the  flat  instrument.  The  length  should  be  such  that 
when  placed  flat  upon  the  gingival  wall  with  one  end  against  the 
axial  wall  the  other  end  protrudes  over  the  gingival  cavo-surface 
angle  of  the  cavity.  The  breadth  should  be  such  that  it  will 
extend  fully  from  the  buccal  wall  to  the  lingual  wall  and  require 
some  crowding  to  make  it  lay  flat.  Simply  lay  this  in  position 
and  begin  building  upon  it,  practically  as  has  been  described  for 
beginning  with  all  cohesive  gold. 

Instead  of  this  flat  cylinder  or  mat,  ordinary  round  cylinders 
may  be  used  by  laying  the  first  in  the  linguo-gingival  angle,  a 
second  in  the  bucco-gingival  angle,  and  a  third  between  the  two. 


116       THE   TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

Or  two  cylinders  may  be  used  that  have  breadth  enough  to  fill 
the  space  from  buccal  to  lingual.  Do  not  condense  the  non- 
cohesive  gold  before  beginning  with  the  cohesive.  Merely 
adjust  it  in  position  with  gentle  pressure,  and  then  condense  it 
by  building  cohesive  gold  upon  it.  Then  proceed  as  in  all 
cohesive  gold  work,  except  that  after  the  filling  is  otherwise 
finished  the  gingival  portion  should  be  very  thoroughly  con- 
densed from  the  surface. 

The  reason  that  non-cohesive  gold  is  safer  in  this  position  is 
that  there  is  less  disposition  to  curl  from  the  margin,  and  if  there 
is  any  disposition  to  curl  from  the  margin  it  is  easy  to  make  it 
tight  by  this  after-condensation,  because  if  not  tight  it  moves 
readily  under  the  blows  of  the  mallet,  while  cohesive  gold  does 
not.  Generally  a  considerable  quantity  of  non-cohesive  gold 
may  be  used  in  this  way  and  greatly  reduce  the  labor  of  making 
the  filling. 

This  plan  of  filling  is  especially  adapted  to  proximate  cavities 
in  the  bicuspids  and  molars.  These  fillings,  as  we  prepare  the 
cavities,  are  not  anchored  in  the  proximate  portion  of  the  cavity, 
but  in  the  step  cut  in  the  occlusal  portion  of  the  tooth.  The 
filling  is  supported  against  the  force  of  mastication  upon  the 
broad,  flat  gingival  wall  as  a  seat,  and  when  non-cohesive  gold  is 
laid  upon  this  in  the  manner  indicated  and  condensed  by  packing 
cohesive  gold  over  it,  it  h^s  all  the  supporting  strength  of  the 
complete  cohesive  gold  filling. 

This  plan  of  using  non-cohesive  gold  is  not  so  well  adapted 
to  proximate  cavities  in  the  incisors  and  cuspids,  for  in  these  we 
have  not  the  opportunity  to  make  strong  occlusal  step  anchor- 
ages, but  must  depend  upon  the  gingival  wall  and  its  angles  in 
part  for  the  strength  of  the  anchorage.  To  use  non- cohesive 
gold  upon  the  gingival  wall  would  materially  diminish  the 
strength  of  this  anchorage.  The  use  of  non-cohesive  gold  upon 
the  gingival  wall  of  proximate  cavities  in  the  incisors  is  not  so 
much  needed,  for  the  reason  that  they  are  in  much  plainer  view 
during  the  progress  of  building  the  filling. 

Strength  of  the   Bite. 

In  the  consideration  of  the  strength  required  in  fillings,  the 
strength  of  the  bite,  or  the  power  with  which  the  teeth  may 
be  closed  upon  food,   is  a  matter  of  first  importance.     This  is 


STRENGTH    OF    THE    BITE.  117 

to  be  considered  with  great  care  by  every  operator,  both  in 
general  and  in  relation  to  each  individual  operation.  The 
strength  required  in  fillings  is  very  much  greater  than  was  for- 
merly supposed.  It  has  been  but  a  few  years  since  we  began 
to  know  definitely  of  the  strength  of  the  bite  or  of  the  strength 
actually  required  of  fillings.  I  believe  the  first  paper  that 
brought  this  prominently  before  the  profession  was  one  which  I 
presented  to  the  Illinois  State  Dental  Society  in  May,  1893. 
Following  that,  two  instruments  were  presented  for  measuring 
the  strength  of  the  bite  at  the  meeting  of  the  World's  Dental 
Congress  in  Chicago,  later  in  the  year  of  1893,  and  very  con- 
siderable interest  was  at  once  manifested  in  this  subject,  which 
has  led  rapidly  to  considerable  changes  in  the  preparation  of 
cavities  and  to  a  radically  new  study  of  the  strength  of  filling 
materials.  These  instruments  were  presented,  one  by  the  late 
J.  J.  R.  Patrick,  of  Belleville,  Illinois,  and  one  by  Dr.  George 
Dennis,  of  Chicago.  The  instrument  we  are  now  using  is  a 
modification  of  the  instrument  presented  by  Doctor  Dennis.  It 
was  immediately  found  that  the  actual  strength  of  the  human 
bite  was  very  much  greater  than  had  been  supposed,  and  that 
the  strength  of  fillings  had  been  insufficient,  and  this  was  the 
cause  of  the  rapid  failure  of  many  fillings,  particularly  proxi- 
mate fillings.  In  order  that  the  instrument  should  well  repre- 
sent the  strength  of  the  bite,  the  surface  upon  which  the  biting 
is  done  should  be  spread  over  the  crowns  of  at  least  two  molar 
teeth,  but  as  it  is  the  force  of  the  bite  is  generally  expended 
upon  a  single  cusp  of  an  upper  tooth  and  a  single  cusp  of  a 
lower  tooth,  which  does  not  give  sufficient  space  to  properly 
present  the  full  power  with  which  the  jaws  may  be  closed  upon 
food.  The  strength  of  the  teeth  is  found  to  be  ample;  one  can 
not  break  a  tooth  with  the  power  of  the  muscles  of  the  jaw, 
unless  the  biting  is  done  on  steel  or  some  other  very  hard  sub- 
stance. In  biting  upon  steel,  or  other  substance  equally  hard, 
the  area  of  tooth  substance  presented  to  the  steel  will  be  very 
small  indeed,  and  by  hard  biting  the  enamel  may  be  fractured. 
But  when  the  substance  bitten  upon  is  soft,  as  a  piece  of  hard 
rubber,  the  tooth  will  sink  into  it  a  little  and  spread  the  area  of 
stress  more  upon  the  surface  of  the  tooth.  On  hard  rubber  or 
the  softer  metals  I  have  never  known  a  person  to  check  the 
enamel  of  a  tooth  in  biting  with  all  the  power  of  the  muscles. 


118       THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

Therefore,  the  teeth  are  abundantly  strong,  unless  we  happen 
to  catch  them  on  a  bit  ot  gravel  or  a  large  bit  of  sand,  or  some- 
thing of  that  kind  that  is  extremely  hard.  Half  a  dozen  stu- 
dents who  tried  the  force  of  their  bite  on  the  Knatho-dyna- 
mometer*  during  one  of  my  lectures  last  year,  registered 
respectively,  155,  190,  250,  220,  225  and  150  pounds.  This 
represents  very  fairly  the  usual  amount,  and  the  variations  in  the 
stress  persons  with  fairly  good  teeth,  and  of  ordinary  habits  in 
their  use,  can  exert.  A  few  will  exert  a  greater  stress,  as  much 
as  275  or  300  pounds.  Many  people  who  use  their  teeth  deli- 
cately will  stop  at  100  pounds  or  less. 

Often  persons  have  registered  100,  130,  and,  occasionally, 
200  pounds  and  over  on  the  central  incisors.  Generally  per- 
sons biting  upon  the  instrument  stop  because  it  hurts  the  peri- 
dental membranes;  they  do  not  register  the  full  power  of  the 
muscles  of  the  jaws.  A  few  tell  me  they  have  exerted  the  full 
power  of  the  muscles  without  pain,  and  in  these  cases  I  suppose 
the  full  power  of  the  muscles  is  registered. 

In  chewing  food  we  use,  as  a  rule,  very  much  more  stress 
than  is  actually  required  to  crush  the  food.  By  trying  the 
crushing  strength  required,  with  the  phago-dynamometer  f  we 
may  find  the  crushing  power  required  for  the  various  foods. 
Filberts  that  school  children  are  in  the  habit  of  crushing  with 
their  teeth  give  a  register  of  from  100  to  150  pounds,  occa- 
sionally more.  In  chewing  meats  much  difference  in  the  required 
stress  is  shown,  good  beefsteak  requires  from  forty  to  sixty 
pounds,  tough  beefsteak  from  sixty  to  eighty  pounds,  occa- 
sionally more.  Mutton  chops  usually  require  from  thirty  to 
forty  pounds,  pork  chops  (loin)  twenty  to  twenty-five  pounds, 
broiled  ham  from  forty  to  sixty  pounds,  etc.  If  any  one  in 
chewing  a  piece  of  beefsteak  will  notice  it  he  will  hear  a  crack- 
ling sound  just  at  the  time  the  fiber  of  the  flesh  is  breaking  up. 
We  can  notice  that  also  in  the  phago-dynamometer,  and  just  at 
the  time  that  the  fiber  is  breaking  up  we  find  that  the  meat 
crushes  out  from  between  the  teeth  and  the  teeth  pass  through 
it  and  come  together.  Most  person  in  chewing  meats  of  any 
kind  crush  their  teeth  through  it  at  a  dash.     A  person  who 


*  An  instrument  for  measuring  the  force  with  which  the  jaws  may  be  closed. 
t  An  instrument  for  measuring  the  crushing  force  necessary  in  chewing  different 
articles  of  food. 


STRENGTH    OF   THE    BITE.  119 

chews  feebly  will  not  do  this.  A  person  who  is  chewing  with 
artificial  teeth  generally  can  not.  A  person  who  can  use  40 
pounds  pressure  upon  artificial  teeth  is  doing  very  well,  and  such 
persons  will  often  find  their  beefsteak  very  tough  ;  but  a  per- 
son who  can  crush  down  200  pounds  can  eat  any  beefsteak.  In 
the  ordinary  chewing  of  beef  or  flesh,  great  force  is  not  required, 
we  may  say,  and  yet,  if  we  catch  upon  a  bone,  or  in  game,  upon 
a  shot,  we  will  get  a  terrible  jolt  upon  the  teeth,  for  we  actu- 
ally use  much  more  than  the  necessary  force.  That  is  as  likely 
to  come  upon  fillings  as  upon  any  other  part  of  the  tooth,  and, 
of  course,  will  give  the  strength  of  the  filling  a  sore  trial. 
In  chewing  meats  the  motion  is  directly  up  and  down  ;  we  do 
not  use  the  lateral  movement  in  chewing  meats.  In  this  we 
copy  the  motions  of  the  carnivorous  animals.  The  carnivorous 
animals  have  their  jaws  hinged  so  that  they  have  but  the  up-and- 
down  motion  used  in  crushing.  We  crush  our  meats  ;  we  do 
not  grind  them.  In  chewing  bread,  or  any  of  the  grains  —  the 
cereal  foods  —  we  do  use  the  lateral  motion  ;  we  grind  them  ,- 
we  can  not  crush  them.  The  more  we  crush  upon  bread  the 
more  we  pack  it  between  the  cusps  of  the  teeth.  A  little  lateral 
motion  will  cause  it  to  go  to  pieces  quite  readily,  but  we  can  not 
crush  even  a  comparatively  soft  bread  crust  with  all  the  force 
that  we  can  put  upon  it  ;  it  will  simply  pack  into  the  sulci  be- 
tween the  cusps  of  the  teeth  and  remain  there.  This  is  shown 
very  readily  with  the  phago-dynamometer.  If  I  put  a  piece  of 
comparatively  soft  crust  in  the  instrument  and  put  on  a  pressure 
of  60,  80  or  100  pounds  it  is  simply  packed  between  the  teeth 
and  has  not  been  cut  through  at  all,  A  litde  lateral  stress  will 
grind  it.  Patients  used  to  come  to  me  saying  that  they  had 
broken  the  cusp  off  of  a  bicuspid,  for  instance,  "just  biting  a 
piece  of  soft  bread."  Sometimes  I  thought  it  was  a  kind  of  a 
joke,  and  sometimes  I  felt  that  it  was  absolute  dishonesty  ;  I  did 
not  know  the  facts  until  I  began  to  try  the  artificial  chewing  of 
food.  Then  I  found  that  there  was  a  substantial  reason  for  it, 
for  in  taking  a  piece  of  bread  crust  between  the  teeth,  without 
having  it  wet,  we  may  crush  with  all  the  force  of  the  muscles  and 
simply  pack  it  between  the  cusps  of  the  teeth  and  bring  to  bear 
a  powerful  splitting  force,  calculated  to  throw  off  a  cusp  from  a 
tooth.  In  this  way  we  lose  the  cusps  of  a  good  many  teeth, 
and  teeth  are  broken   from   plates,  crowns  are  broken,  bridges 


120       THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

are  broken,  ' '  just  in  biting  a  piece  of  soft  bread  crust. ' '  In  these 
several  ways  very  powerful  stress  is  brought  upon  fillings,  and 
cavities  must  be  cut  with  the  view  of  giving  great  strength  to 
the  fillings  and  of  maintaining  the  strength  of  the  teeth. 

It  is  for  this  reason  that  cavities  are  prepared  in  certain  ways. 
In  occlusal  cavities,  as  they  are  formed  by  decay,  the  pulpal  wall 
will  usually  be  rounded  —  will  be  circular.  This  would  be  the 
form  of  the  cavity  after  the  removal  of  the  decay.  Now,  this 
gives  an  opportunity  for  the  rolling  of  fillings  ;  the  filling  is  not 
as  easily  placed  ;  it  is  more  difficult  to  make  a  good  filling  in  such 
a  cavity  and  the  filling  is  more  easily  moved  by  the  force  of  mas- 
tication. It  might  stand  for  a  considerable  time  in  chewing 
beefsteak,  if  it  had  no  bones  in  it,  no  bits  of  gravel,  or  in  chew- 
ing game,  if  there  were  no  shot  that  would  come  upon  a  partic- 
ular portion  of  a  filling  and  cause  it  to  roll.  But  if  the  seat  is 
cut  flat,  then  the  filling  is  supported  in  such  a  way  that  it  is  not 
disposed  to  roll.  Again,  a  still  more  important  point  —  when  in 
a  mesio-occluso-distal  cavity  in  a  molar  or  a  bicuspid,  with  the 
pulp  removed  so  that  the  tooth  is  open  through  from  mesial  to 
distal,  the  breadth  of  the  pulp  chamber  is  considerable  ;  and 
perhaps  there  has  also  been  decay  that  has  further  weakened  the 
dentinal  walls.  If  the  filling  is  finished  in  the  normal  form  of  the 
occlusal  surface,  leaving  the  inclines  of  the  cusps  toward  the 
central  area  of  the  tooth  standing,  the  food  catches  between 
these  inclines  of  the  cusps  upon  the  buccal  and  upon  the  lingual. 
In  this  case  the  patient  crushes  down  upon  a  bread  crust  ;  it 
packs  between  these  inclines  of  the  cusps  and  great  force  is 
brought  upon  them,  and  the  lingual  wall  or  the  buccal  wall  is 
broken  away,  "just  biting  a  piece  of  bread  crust."  For  this 
reason  it  is  necessary  to  take  great  care  in  the  preparation  of  all 
such  cavities.  Never  leave  the  central  incline  of  a  cusp  under 
such  conditions.  No  matter  how  good  it  may  be,  no  matter 
how  perfect  the  enamel  may  be,  no  matter  if  it  is  supported  by 
dentin  immediately  beneath,  never  leave  it.  It  may  be  strong 
toward  the  occlusal,  but  more  toward  the  gingival  it  is  weak,  and 
it  is  that  weak  portion  that  we  need  to  protect.  In  all  of  those 
cases  cut  to  the  crest  of  the  cusp,  at  least  so  that  when  food 
is  packed  between  the  cusps  the  stress  will  come  entirely  upon 
the  filling  ;  let  the  filling  material  take  this  strain  instead  of  the 
cusp   of  the    tooth.     This  will  also  remove  the  possibility  of 


STRENGTH    OF    THE    BITE.  121 

catching  a  shot  or  a  piece  of  bone  upon  the  cusp  of  the  tooth 
and  throwing  it  off.  It  is  that  which  is  caught  upon  the  slope 
toward  the  central  portion  of  the  tooth  that  crushes  it  off,  not 
that  which  is  caught  upon  the  slope  toward  the  axial  surface  of 
the  tooth.  This  is  more  essential  in  the  bicuspids  than  it  is  in 
the  molars,  because  they  are  less  strong.  In  an  ordinary  mesio- 
disto-occlusal  cavity,  where  the  pulp  is  still  retained,  the  inclines 
of  the  cusps  may  be  left  with  perfect  safety.  All  the  strength  of 
the  muscles  will  not  break  it.  But  when  the  length  of  the  walls 
is  increased  by  extending  the  cavity  to  the  floor  of  the  pulp- 
chamber  the  case  is  entirely  different.  The  bicuspids  have 
sharper  inclines  than  the  molars,  and  food  wedged  into  their  sulci 
has  a  greater  splitting  force,  and  in  these,  with  a  mesio-occluso- 
distal  cavity,  and  the  pulp  removed,  it  is  necessary  to  protect  the 
cusps  in  every  way  possible. 

In  building  out  central  incisors  that  have  lost  an  angle  there 
is  only  about  half  the  stress  to  contend  with  as  upon  the  molars  ; 
and  yet,  in  some  instances  there  is  as  much  as  200  pounds 
brought  upon  them.  It  is  not  uncommon  for  persons  to  take  a 
bread  crust  between  the  teeth  and  put  stress  upon  it,  perhaps  the 
full  strength  of  the  muscles  of  the  jaws,  and  then  tear  it  off  with 
the  hand,  putting  an  additional  force  upon  it.  Now,  that  we 
have  to  build  against,  in  building  up  these  angles.  We  must  pre- 
pare for  this  in  the  anchorage  of  the  fillings  and  depend  upon  the 
strength  of  the  gold  when  they  are  built.  In  this  case  it  is  nec- 
essary that  we  have  the  welding  property  of  the  gold  perfect  in 
every  part  ;  any  carelessness  in  the  annealing  of  the  gold  will 
tell  in  the  breakage  of  fillings  in  incisal  angles.  A  little  portion 
imperfecdy  annealed  will  make  a  fault  ;  a  little  imperfection  in 
the  malleting  will  make  a  fault,  either  of  which  will  extend  over 
a  portion  of  the  area  and  cause  a  break.  In  the  preparation  of 
gold  for  such  building  we  should  generally  resort  to  annealing 
upon  a  tray,  allowing  the  gold  to  remain  hot  for  a  considerable 
time  in  order  that  every  particle  may  be  well  annealed.  And 
then  pack  the  gold  with  a  plugger  point  with  a  small  condensing 
area,  and  go  over  every  part  of  it  with  great  care  and  use  enough 
force. 

The  force  required  in  making  fillings,  and  the  strength 
required  of  fillings,  will  depend  largely  upon  the  strength  of  the 
peridental   membranes.      If  the  peridental  membranes  are  not 


122       THE   TECHNICAL    PROCEDURES    IN   FILLING   TEETH. 

Strong  the  patient  will  not  use  the  teeth  very  vigorously,  and 
fillings  of  less  strength  will  answer.  But  be  careful  not  to  under- 
estimate that.  If  the  pulp  has  been  removed  from  a  tooth  and 
it  is  still  somewhat  sore  it  may  be  very  difficult  to  use  sufficient 
force,  and  one  may  be  deceived  ;  for  when  it  is  well  the  patient 
may  put  great  force  upon  it.  One  should  study  each  individual 
case  as  to  the  strength  of  the  peridental  membranes,  the  probable 
habits  of  the  patient  in  chewing  food,  and  build  the  filling  accord- 
ingly. A  person  whose  peridental  membranes  are  strong,  who, 
from  the  appearance  of  the  teeth,  you  would  suppose  used  much 
force  in  masticating  food,  particularly  in  cases  where  teeth  are 
worn,  you  may  expect  that  great  force  is  used  in  the  mastication 
of  food,  and  you  must  build  fillings  accordingly,  and  see  that 
every  portion  of  gold  is  well  annealed  and  malleted  well  home. 
A  careful  study  of  persons  in  regard  to  the  force  they  use  in 
biting  seems  to  me  almost  essential  in  the  practice  of  dentistry. 
I  know  it  is  difficult  to  do  that  without  being  equipped  with  the 
proper  instruments  for  this  study.  I  wish  every  one  could  be 
equipped  with  the  instruments  for  taking  the  bite  of  patients. 
Many  patients  will  become  interested  in  it  and  it  would  afford  a 
fund  of  information  that  would  be  of  great  benefit. 

Finishing   Fillings. 

Except  in  proximate  cavities  in  the  presence  of  a  pro:ximat- 
ing  tooth,  trimming  fillings  to  form  and  finishing  presents  very 
little  difficulty,  and  requires  no  special  preparation  for  the  finish- 
ing before  the  filling  is  introduced.  In  these  it  is  necessary  to 
the  proper  finishing  that  the  teeth  be  separated,  either  before  the 
filling  is  begun,  or  at  some  time  during  the  building  of  it,  to 
allow  room  for  finishing  the  surface  to  the  correct  form.  This 
separating  has  been  described. 

Before  any  finishing  is  begun,  the  cavity  must  be  filled  more 
than  full  at  every  part  to  allow  for  sufficient  trimming  to  remove 
all  instrument  marks,  leaving  a  surface  condensed  to  an  even, 
perfect  hardness. 

In  occlusal,  buccal,  labial  and  lingual  cavities,  the  first 
trimming  may  be  done  with  the  engine,  using  fine-cut  finishing 
burs,  or  corundum  stones,  as  may  be  most  convenient,  or  in 
some  positions  the  trimming  may  be  done  with  the  finishing 
files.      Rotary  instruments  used  in   the  dental  engine  should  be 


FINISHING    FILLINGS.  123 

passed  over  the  surface  of  the  gold  in  some  regular  order,  being 
careful  not  to  cut  too  deeply  in  some  parts,  or  cutting  down 
irregularly.  In  occlusal  cavities,  when  the  bulk  of  the  trim- 
ming has  been  done  in  this  way,  overlaps  will  remain  in  the 
grooves  and  irregularities  of  the  surface.  These  are  best  re- 
moved with  the  discoid  excavator,  or  spoons  20-9-12.  These 
instruments  should  be  very  sharp. 

In  buccal  and  labial  cavities  the  finishing  of  the  gin- 
gival margin  is  the  difficult  point.  Generally  no  attempt 
should  be  made  to  cut  these  fully  down  to  the  enamel  margin 
with  the  bur  or  stone,  but  after  the  first  part  of  the  cutting  has 
been  done,  the  gingival  margin  should  be  trimmed  with  the  files 
or  with  the  finishing  knives.  In  some  positions  this  will  be 
done  easiest  with  the  knives  ;  in  others  it  will  be  done  easiest 
with  the  files.  Generally  the  knives  should  do  the  last  part 
of  the  trimming,  for  the  reason  that  the  sharp  edge  (and  it 
must  be  very  sharp  to  be  of  use)  will  catch  under  the  least  over- 
lap, find  the  exact  enamel  margin,  and  cut  to  it  with  certainty. 
In  using  the  finishing  knives  no  effort  should  be  made  to  cut 
away  a  thick  mass  at  a  single  stroke,  but  rather  so  catch  it  as  to 
remove  thin  shavings  and  pare  down  the  gold  litde  by  little. 
Used  in  this  way  they  will,  in  positions  suited  to  their  use,  cut 
faster  than  any  other  instrument  used  for  this  purpose.  Great 
care  should  be  taken  not  to  overtrim  the  gingival  margin, 
cutting  away  part  of  the  thin  enamel,  or  all  of  it,  leaving 
a  depression.  This  is  very  liable  to  be  done  by  the  careless 
use  of  the  stone,  and  forms  a  depression  in  which  debris  will 
lodge,  setting  up  fermentation  which  will  insure  the  recurrence 
of  decay  at  that  point.  This  error  is  a  very  common  one.  All 
parts  of  the  margin  of  the  filling  should  be  trimmed  exacdy  to 
the  cavity  margins.  This  should  be  so  perfect  that  a  sharp 
edge  or  a  sharp  point  will  slide  from  the  enamel  onto  the  filling, 
or  from  the  filling  onto  the  enamel,  without  the  least  catch  or 
interference  with  the  perfectly  smooth  movement.  All  parts  of 
the  surface  of  the  filling  should  harmonize  with  the  surface  of 
the  tooth  ;  or,  in  other  words,  should  reproduce  the  tooth  form 
with  accuracy.  Then  the  whole  surface  should  be  evenly 
polished.  This  is  best  done  by  using  a  rubber  disk  of  triangular 
form  with  a  sharp  outer  edge  armed  with  pulverized  pumice, 
rotating  rapidly  in  the  engine.     Or,  on  axial  surface  fillings,  the 


124       THE    TECHNICAL    PROCEDURES    IN   FILLING    TEETH. 

sandpaper  disk  may  often  be  used  to  advantage.  When  all 
instrument  marks  have  been  removed  with  this  it  may  be  fol- 
lowed by  a  leather  disk  and  pumice,  which  at  the  last  is  carefully 
run  dry.  This  will  give  a  brilliant  surface.  In  using  the 
engine  great  care  must  be  taken  not  to  develop  too  much 
heat,  as  this  is  likely  to  cause  severe  pain,  and  may  do  perma- 
nent injury  to  the  pulp  of  the  tooth  by  setting  up  hyperaemia. 

A  hard  steel  burnisher  should  not  be  used  on  cohesive 
gold  fillings,  for,  if  used  with  force  enough  to  be  of  value, 
there  is  danger  of  checking  the  enamel  margins,  and  for  the 
reason  that  there  is  no  necessity  for  its  use  if  the  surface  of  the 
filling  has  been  well  condensed. 

Finishing  proximate  fillings. — The  teeth  having  been 
separated  to  give  room,  and  the  filling  built  out  sufficiently  to 
allow  of  its  being  finished  to  the  original  mesio-distal  breadth 
of  the  tooth,  the  gold  will  have  been  packed  very  solidly  against 
the  proximating  tooth.  The  first  thing  is  to  cut  through 
between  this  tooth  and  the  filling  with  a  Koeber  saw,  held  in 
the  Wilson  or  Sibley  frame.  This  cut  should  be  close  against 
the  proximating  tooth,  removing  as  little  gold  as  possible. 
Now,  take  a  thread  saw  (made  by  grinding  from  the  back  of  a 
Koeber  saw  on  an  ordinary  corundum  wheel  until  its  width  is 
reduced  one-half),  place  it  in  the  frame  with  the  teeth  toward 
the  back,  and  pass  this  between  the  filling  and  the  proximating 
tooth  and  work  it  under  the  gingival  margin  of  the  filling  against 
the  neck  of  the  filled  tooth  and  sawing  toward  the  occlusal,  cut 
away  the  overlap  of  gold.  Afterward  the  saw  may  be  turned 
first  one  way  and  then  the  other,  and  cut  away  the  overlap  well 
around  to  the  buccal  and  to  the  lingual  in  case  of  very  broad 
fillings.  Then  the  saws  have  done  their  full  duty.  In  cutting 
away  the  surplus  with  the  saw  especial  care  should  be  had  not  to 
cut  too  much  toward  the  occlusal,  and  thus  cut  away  the  contact 
point.  Now  with  the  finishing  knives  begin  at  the  gingival,  and 
cutting  fine  shavings  (the  krtives  must  be  sharp),  remove  any 
remaining  overlap  first  and  shave  the  proximate  surface  and  the 
gingival  portion  of  the  embrasures  to  the  required  form.  When 
the  hand  has  become  trained  to  the  use  of  these  knives,  and  they 
are  kept  sharp,  this  part  of  the  work  is  quickly  done  and  well 
done. 

The    buccal  and   lingual    embrasures   are   then   to   be 


FINISHING    FILLINGS.  125 

trimmed  to  form,  and  the  contact  which  has  been  left  flat  with 
the  saw  must  be  rounded.  This  part  of  the  work  is  best  done 
with  the  file-cut  finishing  files. 

The  blades  of  these  files  must  be  sharp  to  do  this  work 
well.  When  they  have  become  dulled  they  are  easily  sharpened 
with  slips  of  Arkansas  stone,  made  for  this  purpose.  Each  blade 
is  to  be  carefully  ground  sharp  by  drawing  the  stone  back  and 
forth  against  it.  Generally,  oil  should  be  used  on  the  stone. 
When  the  edge  of  the  stone  has  become  dulled  or  gaped  it  may 
be  sharpened  by  whetting  on  fine  emery  paper  laid  flat  on  a  table. 
Generally  these  files  may  be  used  with  the  thumb  and  palm 
grasp,  and  the  flat  sides  applied  to  the  gold,  and  with  short, 
strong  strokes  almost  parallel  with  the  long  axis  of  the  tooth, 
the  excess  of  gold  is  quickly  removed.  As  the  margins  of  the 
blades  of  these  files  are  thin  and  sharp,  they  can  pass  well  into 
the  embrasure  toward  the  contact  point,  rounding  the  surface 
just  up  to  that  point  without  cutting  over  it.  This  is  done  first 
on  the  buccal  and  then  upon  the  lingual,  and  the  contact  point 
sharply  rounded,  and  the  embrasures,  lingual  and  buccal,  rounded 
to  the  proper  form. 

Obtaining  this  marble-like  roundness  of  the  contact 
points  is  the  critical  requirement  in  finishing  proximate 
fillings.  If  the  surface  is  cut  flat,  the  contact  will  grasp  and  hold 
food  between  the  teeth  and  cause  annoyance  and  pain,  and  cause 
injury  to  the  gum  septum  by  forcing  the  confined  food  against  it. 
Neglect  of  this  precaution  has  caused  the  loss  of  thousands  of 
otherwise  good  fillings,  and  the  teeth  themselves,  either  by 
causing  a  recurrence  of  decay  or  by  inducing  disease  of  the 
peridental  membrane. 

The  occlusal  surface,  if  the  case  be  a  molar  or  bicuspid,  is  to 
be  trimmed  and  finished  as  described  for  occlusal  fillings,  after 
which  corrections  are  made  in  the  occlusal  third  of  the  proximate 
surface,  and  the  whole  filling  polished. 

Polishing  of  proximate  surface  fillings  should  be  done 
partly  with  tape  and  partly  with  disks  in  the  engine.  Tapes 
should  be  used  for  polishing  the  gingival  two-thirds  of  the  sur- 
face, or  all  of  that  portion  of  the  filling  to  the  gingival  of  the 
contact  point,  having  especial  care  not  to  cut  away  the  contact 
point.  Narrow  strips  should  be  used.  The  embrasures,  buccal 
and  lingual,  should  be  polished  with  disks,   usually  not  more 


126       THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

than  five-eighths  of  an  inch  in  diameter,  in  the  engine.  The 
disks  should  never  be  allowed  to  pass  the  point  of  con- 
tact, as  they  would  quickly  ruin  the  filling  by  cutting 
away  the  contact  point,  but  should  be  confined  to  the 
embrasures  and  the  buccal  and  lingual  margins.  When  this  has 
been  completed  satisfactorily,  a  very  fine  tape  may  be  passed 
a  few  times  over  the  contact  point,  rounding  it  and  completing 
the  polish. 

The  importance  of  the  form  of  fillings  will  be  consid- 
ered more  fully  when  the  causes  of  caries  and  the  conditions 
of  its  occurrence  have  been  presented. 

Filling  with  Amalgam. 

I  will  preface  the  consideration  of  the  manipulative  proced- 
ures in  filling  with  amalgam  by  saying  that  every  detail  of  the 
cavity  preparation  should  be  the  same  as  for  filling  with  gold, 
except  that  convenience  points  for  starting  the  filling  need  not 
be  made.  Neither  is  it  quite  so  explicitly  required  that  conven- 
ience forms  of  the  walls  for  access  be  so  rigidly  observed, 
though  there  should  not  be  much  difference.  If  possible,  the 
anchorage  should  be  stronger  than  for  gold,  and  as  amalgam  is 
so  much  used  for  very  badly  decayed  teeth,  especially  in  bicuspids 
and  molars  from  which  the  pulps  have  been  removed,  advantage 
should  be  taken  of  the  pulp  chamber  to  strengthen  the  anchor- 
age. The  pulp  chamber  should  be  filled  solidly  with  amalgam 
to  the  pulpal  orifice  of  the  root  canals  when  using  it  in  pulpless 
teeth.  With  the  amalgam  we  are  using  nowadays  the  teeth  will 
not  be  discolored  if  the  filling  is  properly  made.  The  amalgam 
exposed  upon  the  surface  will  discolor  up  to  the  margins,  but 
the  amalgam  that  is  in  contact  with  the  walls  of  the 
cavity  will  not  discolor,  and  consequently  will  not  discolor 
the  tooth.  It  is  only  when  the  amalgam  filHng  leaks  about  the 
margins  that  the  tooth  is  discolored  by  it,  and  as  we  can  now 
use  amalgams  that  do  not  shrink,  discolorations  of  the  teeth  will 
occur  only  through  imperfect  manipulation.  The  fact  that 
amalgams  used  in  the  past  and  until  very  recently  would  shrink, 
causing  leakage,  is  the  reason  why  teeth  filled  with  it  have  been 
so  generally  discolored.  It  is  not  easy,  however,  to  make 
mechanically  perfect  amalgam  fillings,  and  for  one  to  succeed 
uniformly  requires  skill  and  the  utmost  care  in  every  detail. 


FILLING   WITH    AMALGAM.  127 

Amalgam  is  admissible  only  in  the  bicuspids  and 
molars. 

All  cavities  filled  ■with  amalgam  must  have  continu- 
ous surrounding  walls  during  the  building  of  the  filling. 

We  can  not  build  up  a  corner  of  a  tooth  with  amalgam  and 
expect  good  adaptation  to  the  walls,  for  the  material  is  plastic, 
and,  when  pressed  upon,  the  whole  body  of  the  filling  is  liable 
to  movement.  To  prevent  this,  complete  surrounding  walls  are 
a  necessity.  Therefore,  whenever  a  cavity  presents  that 
has  not  four  surrounding  w^alls,  the  missing  w^alls  must 
iDe  supplied  by  artificial  walls.  This  is  done  by  the  applica- 
tion of  the  matrix.  It  is  to  be  used  in  filling  all  proximate  cavi- 
ties, and  in  any  others  in  which  one  wall  is  broken  down. 

Placing  the  matrix. — When  a  proximate  cavity  is  other- 
wise ready  for  filling  with  amalgam,  a  slip  of  thin  metal  plate 
(copper,  brass,  German  silver  or  steel)  is  cut  of  sufficient  width 
to  extend  from  the  occlusal  surface  of  the  tooth  to  near  the  gin- 
gival line,  or  far  enough  to  fully  cover  the  gingival  margin  of  the 
cavity,  and  long  enough  to  encircle  about  half  the  tooth.  The 
rubber  dam  having  been  applied  before  the  excavation  of  the 
cavity  was  completed,  this  slip  is  passed  between  the  teeth  and 
roughly  fitted  to  see  that  the  width  and  length  are  right.  Then 
at  the  corners  to  the  gingival  a  little  ear  is  turned  with  the  pliers 
that  will  prevent  a  ligature  from  slipping  off  to  the  gingival,  when 
it  is  drawn  tightly  around  the  tooth.  Also  the  cut  ends  of 
the  metal  should  be  so  bent  that  the  sharp  angles  will 
not  cut  the  ligature.  This  is  now  passed  between  the  teeth  so 
as  to  cover  the  proximate  portion  of  the  cavity.  Then  a  ligature 
is  thrown  two  or  three  times  around  the  tooth,  including  the 
matrix,  tightly  drawn  and  tied.  This  is  often  a  difficult  operation 
for  the  beginner,  but  after  a  little  experience  the  manipulation 
comes  easy  enough  in  most  cases.  A  few  cases  occur  where  the 
conditions  arc  unfavorable  and  try  one's  wits,  but  these  can  be 
successfully  done  by  a  little  effort.  When  this  has  been  done  the 
Perry  separator  is  applied  over  the  matrix,  or  in  many  cases  the 
matrix  may  be  held  with  the  separator  without  the  ligature.  It 
is  just  as  important  to  separate  the  teeth  for  amalgam 
fillings  as  for  gold  fillings,  and  on  no  account  should  this  be 
neglected  in  cases  requiring  it.  After  the  preparation  is  other- 
-wise  complete,  a  careful  examination  of  the  gingival   margin  of 


128       THE   TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

the  cavity  should  be  made  to  see  that  the  matrix  is  close  at  that 
point,  and  if  it  is  not,  it  should  be  brought  close,  by  inserting  a 
small,  soft  wood  wedge  from  the  lingual  side  with  just  suffi- 
cient force  to  bring  the  matrix  close.  This  is  most  likely  to  be 
needed  in  molars  that  have  broad,  flat,  proximate  surfaces. 

Preparing  the   Amalgam. 

It  is  of  great  importance  to  obtain  in  the  beginning  the  right 
proportions  of  alloy  and  mercury.  This  proportion  will  vary 
with  the  alloy  used.  Of  the  higher  grades  of  alloy  we  are 
at  present  using,  this  proportion  is  very  nearly  equal  parts  by 
weight,  but  generally  a  slightly  greater  proportion  of  mercury  is 
required  ;  or  about  52  per  cent.  This  proportion  should  be 
carefully  determined  for  the  alloy  used,  and  the  proportions 
weighed  for  each  mix.  We  think  this  of  such  importance  in  our 
infirmary  work  that  we  have  this  weighing  done,  and  the  prop- 
portions  put  in  separate  capsules.  I  have  also  found  that  to 
undertake  to  knead  the  alloy  with  too  much  mercury  results  in 
very  imperfect  kneading  and  makes  a  weak  amalgam,  while  to 
knead  with  too  little  mercury  also  makes  a  very  weak  amalgam, 
and  a  mass  that  is  too  granular  and  stiff  to  work  well. 

Kneading. 

The  first  of  the  kneading  is  done  best  in  a  wedgewood  or 
ground-glass  mortar.  This  should  be  continued  until  all  of  the 
fillings  are  incorporated  with  the  mercury,  when  it  should  be 
turned  into  the  palm  of  the  hand  and  vigorously  kneaded  with 
the  fingers.  For  this  work  the  hand  should  be  as  dry  as  possi- 
ble. This  kneading  should  be  continued  until  the  mass  is  per- 
fectly soft,  plastic  and  free  from  granulation.  If  in  the  kneading 
the  mass  becomes  too  very  soft  there  is  too  much  mercury  in  the 
mix,  and  so  soon  as  that  is  determined  a  portion  of  the  mercury 
should  be  removed  by  squeezing  the  mass  between  the  fingers 
and  the  kneading  immediately  continued,  for  if  -the  mass  is 
allowed  to  stand  for  even  a  few  moments  in  this  condition  it  is 
likely  to  become  too  stiff  for  rekneading.  When  sufficiently 
kneaded,  the  mass  should  not  very  readily  break  when  rolled  into 
a  long  roll  in  the  palm  of  the  hand.  Everything  should  be  in 
exact  readiness  to  insert  the  filling  and  the  packing  immediately 


FILLING   WITH    AMALGAM.  129 

proceeded  with,  for  if  the  alloy  is  just  what  it  should  be,  the 
mass  will  begin  to  stiffen  very  quickly,  and  possibly  become  unfit 
to  work  before  the  packing  is  completed. 

Packing   Amalgam    Filling. 

The  importance  of  the  best  form  of  instrument  for  packing 
amalgam  can  hardly  be  overestimated.      Until   I   had  examined 
this  over  and  over  again,  experimentally,  under  conditions  which 
enabled  me  to  determine  results,  I  had  no  idea  of  the  importance 
of  the  instrument  forms   for  this  purpose.     The  one  thing  need- 
ful in  packing  amalgam  is  to  grasp  the  mass  as  a  whole  as  nearly 
as  possible,  and  compress  it  into  the  cavity.     The  whole  prin- 
ciple of  making  perfect  work  is  contained  in  the  one  word, 
compression.     Therefore,  the  cavity  must  be  a  simple  one  with 
complete  surrounding  walls,  or  must  be  converted  into  a  simple 
cavity  by  supplying  any  missing  walls  with  the  matrix.     Then 
the  instrument  point  should  be  flat  and  as  large  as  the  cavity 
will  conveniently  admit,  and,  when  practicable,  its   form  should 
be  such  as  to  as  nearly  fit  the  cavity  as   possible.      With  it  and 
the  walls  of  the  cavity  the  mass  of  amalgam  should  be  grasped 
as  perfectly  as  possible  and  powerfully  compressed,  so  as  to  force 
the  amalgam  into  all  parts  of  the  cavity.     About  all  the  force  the 
hand  is  capable  of  should  be  brought  upon  it  and  maintained  for 
an  instant.      Then  more  of  the  mass  is  added  and  again  pressure 
applied.      This  should   be  done  as  rapidly  as  perfect  work   will 
admit,  until  the  cavity  is  full  and  much  more  than  full.      Indeed, 
more  of  the  mass  should  be   added  and  compressed  as  long  as 
compression  of  the  mass  in  the  cavity  can  be  made  by  adding  to 
the  surface,  for  the  time  comes  when   the  m.ass  added  simply 
spreads  out  over  the  cavity  walls.      If,  during  the  packing,  there 
are  narrow  parts  of  the  cavity  or  irregularity  of  walls  into  which 
the  instruments  do  not  go  well,  a  smaller  instrument  should  be 
used  to  pack  the  amalgam  into  them.      These  should  not  be  used 
with  such  force  as  to  crush   into  the  mass  and   chop  it  up,   but 
only  with  such  force  as  will  compress.     When  the  cavity  is  full 
it  should  be  allowed  to  rest  undisturbed  for  a  few  minutes  to  give 
it  time  to  stiffen  a  little  before  attempting  to  remove  any  of  the 
surplus. 


130       THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

Instruments. 

In  the  lists  of  instruments  there  are  three  round  points  of 
different  sizes  from  small  to  large  for  the  more  ordinary  work, 
and  then  there  are  two  pairs  arranged  with  special  reference  to 
filling  occluso-proximate  cavities.  One  of  each  of  these  pairs 
will  fit  fairly  well  into  the  proximate  portion  of  these  cavities, 
and  the  other  into  the  step.  They  grasp  and  compress  the  mass 
well  in  either  of  these  positions.  All  of  them  are  serrated  to 
prevent  slipping  and  sliding.  These  instruments  should  be  used 
in  all  amalgam  work. 

Heretofore  many  dentists  have  used  burnishers  to  pack  amal- 
gam fillings,  thinking  they  could  burnish  and  amalgam  to  the 
walls  of  the  cavity.  This  is  a  popular  error.  I  once  supposed 
I  could  do  this,  and  could  prove  it  by  burnishing  amalgam  onto 
a  tooth-brush  handle,  causing  it  to  stick  so  firmly  that  I  could 
build  a  great  mass  upon  it  and  the  whole  would  cling  very 
tightly.  But  on  prying  this  off  and  examining  the  surface  that 
stuck  so  well  with  the  microscope,  I  found  it  full  of  fine  bubbles. 
In  trying  some  of  these  in  an  aniline  dye  I  found  that  these  bub- 
bles became  filled  with  the  colored  fluid.  In  trying  this  in  cav- 
ities in  teeth  and  breaking  the  tooth  after  the  amalgam  was  hard, 
I  found  the  same  thing  occurred.  Finally,  I  became  convinced 
that  the  endeavor  to  make  a  perfect  amalgam  filling  with  a  bur- 
nisher was  a  failure.  The  thing  simply  can  not  be  done.  The 
amalgam  will  flake  up  from  the  wall  and  the  adaptation  be 
imperfect. 

Finishing   Amalgam    Fillings. 

When  the  amalgam  filling  has  stood  a  few  moments  to  stiffen 
in  some  degree,  the  surface  should  be  trimmed  to  form  with  a 
discoid  or  spoon  excavator,  if  on  an  occlusal  surface,  and  care- 
fully burnished  toward  the  walls,  using  a  light  pressure  that 
will  not  be  liable  to  move  the  mass  as  a  whole.  If  upon  an  axial 
surface,  as  the  buccal,  it  may  very  conveniently  be  trimmed  with 
the  finishing  knives  and  all  overlaps  removed,  and  then  carefully 
but  lightly  burnished.  If  an  occluso-proximate  filling,  trim  the 
occlusal  portion  before  removing  the  separator,  as  this  work  will 
give  a  little  more  time  for  the  mass  to  harden  to  prevent  the  fill- 
ing being  crushed  by  the  teeth  dropping  together. 

When  the  separator  is  removed  the  matrix  will  be 


THE    CEMENTS.  131 

firmly  held  between  the  filling  and  the  proximating  tooth. 

Any  attempt  to  pull  this  out  is  liable  to  injure  the  filling.  In 
this  case  straighten  out  the  ends  of  the  matrix  to  the 
lingual  and  to  the  buccal  and  reapply  the  separator  with 
the  matrix  between  the  claw^s.  Then  tighten  the  sepa- 
rator sufficiently  to  loosen  the  matrix  and  remove  it. 

Now,  while  the  separator  is  in  place,  with  the  finishing  knives 
trim  the  proximate  surface  to  form  and  remove  all  overlaps  about 
the  margins.  Then  burnish  lightly,  remove  the  separator  and 
the  rubber  dam.  Be  careful  to  note  the  occlusion,  and  if 
a  cusp  of  an  opposing  tooth  strikes  the  filling,  trim  it 
down  so  that  there  may  be  no  danger  of  injury  to  the  fill- 
ing from  that  cause. 

Trimming  to  form  as  described  is  very  important,  because  it 
can  be  done  at  this  time  while  the  amalgam  is  still  but  partially 
hardened,  with  ease,  and  very  quickly.  If  we  wait  until  the 
amalgam  is  fully  hard  it  is  a  tedious,   difficult  operation. 

The  patient  may  now  be  dismissed  for  one,  two  or  three 
days,  as  may  be  mutually  convenient,  or  until  the  amalgam  is 
fully  hard.  Then  the  whole  filling  must  be  polished.  This 
polishing  is  practically  the  same,  is  done  with  the  same 
instruments  as  a  gold  filling,  and  must  be  done  with  the  same 
care.  In  proximate  fillings  it  is  very  often  necessary  to  re- 
apply the  separator  to  properly  finish  the  proximate  surface 
and  the  contact  point. 

The   Cements. 

The  cements  at  present  available  for  use  in  filling  operations 
are  the  oxy-chloride  of  zinc  and  the  oxy-phosphate  of  zinc.  The 
composition  of  these  you  have  already  learned  in  the  chemical 
laboratory.  Formerly  the  oxy-chloride  of  zinc  cement  was  much 
used,  but  since  the  introduction  of  the  oxy-phosphate  it  has  fallen 
into  disuse  on  account  of  the  very  irritating  qualities  of  its  fluid 
portion.  The  phosphate  of  zinc  cement  is  very  much  less  irrita- 
ting and  is  generally  preferred  for  this  reason.  The  cements  are 
received  from  the  dealer  in  two  separate  bottles,  the  one  contain- 
ing the  powdered  oxide  of  zinc  and  the  other  the  fluid.  In  use 
a  small  portion  of  the  powder  is  placed  upon  a  porcelain  or  glass 
slab,  and  a  drop  or  two  of  fluid  is  placed  beside  it.  The  two  are 
then   drawn  together  and  thoroughly  mixed  by  rubbing  them 


132       THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

together  with  a  spatula.  This  spatulation  should  be  continued 
until  a  very  smooth,  creamy  mass  has  been  formed.  The  mix- 
ture of  the  oxy-phosphate  should  be  much  thicker  and  stififer 
than  the  mixture  of  the  oxy-chloride  to  obtain  the  best  results 
with  the  respective  cements.  Indeed,  the  oxy-chloride  may  be 
mixed  so  thin  and  soft  as  almost  to  flow  and  yet  become  very 
hard  and  firm;  while  the  oxy-phosphate,  to  produce  the  best  mass, 
should  be  rather  stiff,  yet  it  may  be  quite  plastic. 

As  yet,  there  has  been  very  little  careful  examination  of  the 
physical  properties  of  these  cements.  We  do  not  know  accu- 
rately the  proportions  of  powder  and  fluid  required  to  produce 
the  best  results.  It  is  probable  that  these  vary  with  the  different 
makes  of  these  cements,  and  also  with  the  age,  for  the  fluids 
seem  to  be  inconstant  in  their  properties.  It  has  been  the  con- 
stant habit  of  dentists  to  mix  them  without  any  rule,  simply 
observing  the  plasticity  of  the  mass  produced,  being  governed 
entirely  by  the  eye  and  the  observation  of  the  results.  This 
must  be  regarded  as  a  very  inaccurate  method  of  using  this 
material,  but  so  long  as  we  are  without  more  accurate  knowledge 
of  it  than  this  gives,  we  can  only  follow  it.  Very  recently  some 
work  has  been  done  on  the  physical  properties  of  the  cements  by 
Doctor  Wedelstaedt,  of  St.  Paul,  and  by  Doctor  Ames,  of  Chi- 
cago. In  this  work  it  has  been  shown  that  most  of  the  cements 
are  readily  permeated  by  moisture,  while  some  are  not,  and  also 
that  some  of  the  cements  will  shrink  badly  while  hardening. 

In  mixing  the  oxy-phosphate  it  seems  to  be  best  to  draw  the 
powder  into  the  fluid  and  incorporate  it  little  by  little  until  the 
required  stiffness  of  the  mass  has  been  acquired.  Just  what  this 
should  be  can  not,  in  the  absence  of  carefully  conducted  experi- 
ments, be  definitely  stated.  In  practice  it  is  varied  with  the 
particular  use  to  be  made  of  the  particular  mix.  If  for  filling 
and  setting  crowns,  in  which  case  great  plasticity  is  required, 
the  consistency  of  very  thick  cream  is  usually  acquired,  and  this 
very  thoroughly  spatulated  and  used  quickly,  or  before  it  has 
begun  to  stiffen.  If  for  filling  cavities  in  teeth,  more  of  the 
powder  is  added  and  the  mix  made  stiffer,  and  the  spatulation 
continued  somewhat  longer,  so  that  the  mass  assumes  a  putty- 
like consistence.  It  seems  to  be  the  general  notion  that  when 
mixed  in  this  way  a  much  stronger  mass  is  formed.  This  idea 
is  strongly  supported  by  some  recent  physical  experiments,  yet 


THE    CEMENTS.  133 

these  have  not  been  in  sufficient  number,   nor  have  they  been 
sufficiently  varied  as  to  conditions  to  give  certain  working  data. 

These  cements  are  not  impervious  to  moisture.  Some 
experiments  have  recently  been  made  as  to  the  qualities  of 
the  cements  with  regard  to  exclusion  of  moisture,  and  it  has 
been  found  that  none  of  them  are  actually  impermeable,  while 
many  of  those  on  the  market  admit  moisture  readily.  As  yet, 
we  do  not  know  with  any  degree  of  certainty  upon  what  these 
differences  depend.  They  are,  however,  very  important.  Other 
things  being  equal,  the  cement  that  is  nearest  moisture-tight  is 
the  best  for  use.  Any  one  may  try  cements  by  making  experi- 
mental fillings  and  placing  them  for  a  day,  or  two  or  three,  in  a 
solution  of  aniline  dye,  and  then  breaking  them  open  and 
observing  the  penetration  of  the  color  into  the  mass  of  the 
material.  Some  of  the  cements  will  be  penetrated  through  and 
through  in  a  very  short  time,  while  others  will  resist  for  a 
longer  time. 

It  appears  from  experiments  already  made  that  those  cements 
which  are  not  permeable  by  moisture  shrink  badly  while  setting. 
This  shrinkage  renders  them  a  poorer  material  for  use  than  some 
of  those  that  are  in  a  degree  penetrable  by  moisture. 

When  made  into  fillings  in  teeth  the  cements  do  not 
resist  perfectly  the  solvent  action  of  the  oral  secretions. 
Thisy  are  slowly  dissolved,  or  waste  away.  They  are,  therefore, 
not  very  permanent  fillings.  In  this  regard  great  differences  are 
observed.  In  a  few  cases  cement  fillings  have  done  excellent 
service  for  many  years,  seemingly  resisting  the  action  of  the  oral 
secretions  perfectly.  In  the  majority  of  cases,  however,  they 
dissolve  away  within  two  or  three  years,  and  in  many  instances 
within  a  few  months.  We  have  not  yet  such  a  knowledge  of  the 
conditions  of  these  variations  as  will  enable  us  to  control  them, 
and  must  therefore  regard  cement  fillings  as  temporary  in  their 
nature  and  qualities,  expecting  to  renew  them  at  frequent  inter- 
vals. 

Use  of  the  Cements. 

The  cements  are  used  for  setting  crowns  and  bridges,  for 
temporary  fillings,  and  for  preserving  for  a  time  teeth  that  are 
very  badly  broken  down,  or  in  other  conditicHis  which  seem  to 
render  the  use  of  the  metallic  fillings   undesirable  at  the  time. 


134       THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

They  may  also  be  used  for  temporary  fillings  in  cases  of  very 
sensitive  dentin  for  the  purpose  of  allaying  the  extreme  sensitive- 
ness, which  is  generally  found  to  disappear,  in  large  part  at 
least,  within  a  few  weeks  or  months.  They  may  also  be  used 
for  temporary  fillings  in  cases  of  hyperaemia  of  the  dental  pulp 
with  marked  advantage,  for  the  reason  that  their  conductivity  of 
thermal  impressions  is  less  than  that  of  the  metals,  though  in  this 
respect  gutta-percha  is  much  better  than  the  cements  ;  also  they 
may  be  used  in  capping  exposed  pulps. 

The  cements  are  also  much  used  for  sealing  treatments  in 
pulp-chambers  and  root-canals.  This  last  use  of  the  cements  is 
not  good  practice.  They  do  not  perfectly  exclude  moisture. 
Gutta-percha  is  much  better  for  this  purpose  for  the  reasons,  first, 
that  gutta-percha  is  impermeable  to  fluids,  and  moisture-tight 
fillings  can  be  made  with  it;  second,  gutta-percha  is  much  more 
easily  removed  from  the  cavity  in  opening  it  for  changes  of  the 
applications.  It  is  very  painful  to  cut  out  a  cement  filling  when 
the  peridental  membrane  of  the  tooth  is  sore,  while  gutta-percha 
may  be  softened  by  heat  and  removed  with  very  little  pain. 

Filling  with  Cement. 

In  filling  cavities  with  cement  the  preparation  should  be  well 
made,  all  of  the  walls  being  cleaned  by  perfectly  removing  all 
carious  dentin  to  sound  tooth  structure,  and  the  walls  and  mar- 
gins trimmed  smooth.  Some  degree  of  retention  should  also  be 
given  to  the  cavity  form,  but  this  is  not  so  imperative  as  with 
metal  fillings. 

-The  cavity  should  be  perfectly  dry  at  every  part,  for  in  this 
case  we  may  expect  that  the  cement  will  adhere  strongly  to  the 
cavity  walls  and  in  part  sustain  the  filling  in  position.  The 
cement  should  be  mixed  with  as  much  of  the  powder  as  will 
work  into  a  plastic  mass  and  spatulated  vigorously  until  it  has 
begun  to  stiffen,  and,  when  at  the  consistence  of  putty,  should 
be  packed  into  the  cavity  in  moderately  small  masses,  using  as 
much  force  as  the  consistence  will  allow,  adding  piece  after  piece, 
until  all  parts  of  the  cavity  are  full  and  over-full.  Then  a  few 
moments  should  be  allowed  for  the  cement  to  stiffen  a  little  more, 
after  which  the  filling  is  trimmed  to  form  with  the  finishing 
knives.  In  this  trimming  the  cement  should  be  so  stiff  that  the 
stickiness  shall  have  disappeared,  for  it  is  only  just  at  this  time 


GUTTA-PERCHA.  135 

that  it  can  be  cut  smoothly  without  dragging.  After  trimming 
it  may  be  burnished  Hghdy,  and  if  necessary  smoothed  with 
polishing  strips. 

After  the  filling  is  completed  it  should  be  protected  from 
moisture  for  some  minutes,  the  longer  the  better,  as  the  cement 
will  become  harder.  It  seems  that  when  moisture  is  admitted 
early  a  part  of  the  phosphoric  acid  is  dissolved  out  of  the  cement, 
robbing  it  of  a  part  that  is  necessary  for  the  most  complete  hard- 
ening of  the  mass. 

These  general  principles  should  be  observed  in  all  uses  of 
cements.  Softer  masses  must  be  used  in  setting  crowns  and  some 
other  operations  requiring  a  plasticity  approaching  a  fluid  condi- 
tion, but  it  should  be  remembered  that  this  renders  the  cement 
less  strong  and  more  soluble,  and  is  to  be  avoided  whenever  the 
conditions  of  the  case  in  hand  will  allow. 

Gutta-percha. 

Gutta-percha  is  used  for  various  purposes  in  connection  with 
filling  operations.  The  best  form  for  this  purpose  is  the  ordinary 
base-plate  gutta-percha.  Besides  this,  however,  a  multitude  of 
makes  for  the  purpose  of  filling  teeth  are  found  in  the  market. 
None  of  these  are  superior  to  the  ordinary  base-plate,  and  the 
greater  number  of  them  are  very  inferior.  Many  of  them  seem 
to  be  mixtures  of  gutta-percha  and  wax  that  soften  very  readily 
by  heat.     These  are  especially  to  be  avoided. 

Gutta-percha  is  the  best  material  we  have  for  root  filling,  for 
sealing  dressings  in  root-canals,  and  for  most  of  the  temporary 
stoppings  used  in  connection  with  treatment  cases.  Under 
certain  conditions  it  is  also  an  excellent  material  for  more  or  less 
permanent  fillings  in  cavities  in  the  teeth. 

Filling  with  Qutta-percha. 

In  filling  cavities  in  teeth  with  gutta-percha  the  cavity  should 
be  prepared  almost  as  for  gold  or  amalgam,  but  generally  con- 
venience points  for  starting  may  be  dispensed  with.  The  cavity 
should,  however,  be  made  as  strongly  retentive  as  possible. 
When  otherwise  ready  for  filling,  every  portion  of  the  cavity  walls 
should  be  moistened  with  eucalyptol  or  oil  of  cajuput.  These 
oils  take  strongly  to  the  cavity  walls  and  also  dissolve  slightly  the 
surface  of  the  gutta-percha  as  it  comes  in  contact  with  it.     The 


136       THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

oil  then  diffuses  through  the  mass  of  the  gutta-percha  and  is  lost, 
apparently,  leaving  the  gutta-percha  adhering  firmly  to  the  cavity 
walls.  Therefore,  for  this  purpose  the  cavity  -walls  should 
only  be  moistened.  No  excess  of  the  oil  should  be  allowed 
to  remain  in  the  cavity,  as  the  effect  will  be  to  soften  the  whole 
mass  of  the  filling. 

Prepare  the  gutta-percha  by  gently  warming  it  over 
the  flame  of  the  alcohol  lamp,  or  upon  a  warm  tray.  Care 
should  be  had  not  to  heat  the  gutta-percha  too  hot.  This  will 
develop  an  inordinate  stickiness  of  the  mass,  and  it  will  not 
again  become  fully  hard;  the  quality  of  the  material  is  per^ 
manently  injured. 

When  it  is  made  just  plastic  by  heat,  convey  it  to  the  cavity 
in  small  pieces  and  build  the  filling  up  from  the  most  convenient 
angle  or  wall  of  the  cavity  piece  by  piece,  sticking  the  warm 
pieces  to  the  mass  in  the  cavity  with  a  considerable  pressure,  and 
condensing  well  against  all  walls  and  margins.  In  this  work  it  is 
well,  if  possible,  to  add  no  more  of  the  material  than  will  just  fill 
the  cavity,  having  none  to  remove  in  trimming.  If,  however,  a 
surplus  has  been  added,  warm  a  small  flat  burnisher  sufficiently 
to  quickly  soften  the  gutta-percha  upon  contact,  and  with  this 
cut  away  the  surplus,  and  immediately  condense  and  adjust  the 
surface  of  the  filling  with  a  cold  burnisher  that  has  been  laid 
ready.  The  finish  should  generally  be  made  entirely  with  the 
burnisher,  as  we  can  not  polish  the  surface  of  the  filling  by  any 
of  the  usual  means.  By  waiting  until  the  filling  is  fully  hard  it 
may  be  trimmed  with  a  sharp  knife,  but  the  edge  must  be  very 
sharp  to  cut  smoothly.  This  is  the  best  instrument  for  remov- 
ing overlaps  and  making  a  good  finish  of  margins. 

Another  plan  of  filling  with  gutta-percha  that  is  useful  in 
many  cases,  especially  cavities  of  easy  access,  is  to  form  a  mass 
that  will  just  fill  the  cavity  and  warm  it  only  sufficiently  to  obtain 
the  necessary  plasticity, (and  insert  the  whole  filling  in  one  piece, 
condensing  with  a  broad,  cold  instrument,  afterward  finish  as 
before  described. 

Much  experience  is  required  to  handle  gutta-percha 
well,  but  when  once  the  manipulation  has  been  learned  it  is  not 
difficult,  and  requires  but  little  time.  It  should  be  the  only 
material  used  for  sealing  in  dressings,  and  for  the  temporary 
stoppings  in  connection  with  treatments. 


EXPOSURE    AND    REMOVAL    OF   THE    DENTAL    PULP.        137 

Gutta-percha  is  too  soft  for  permanent  fillings  in  any  positions 
that  are  exposed  to  the  stress  or  friction  of  mastication.  In 
some  cavities,  where  it  will  not  be  exposed  to  wear,  it  will  do 
most  excellent  service.  It  is  especially  to  be  recommended  for 
fillino-  cavities  in  the  buccal  surfaces  of  the  teeth  of  old  people, 
especially  those  that  are  in  large  part  in  the  cementum,  and 
extend  beneath  the  free  margin  of  the  gum. 

It  is  often  useful  as  fillings  in  the  temporary  teeth  for  chil- 
dren. By  renewing  it  from  time  to  time  these  teeth  may  be 
made  useful  until  removed  in  the  shedding  process.  However, 
children  often  wear  it  out  of  cavities  rapidly,  and  it  needs  to  be 
very  frequently  renewed. 

Gutta-percha  is  also  very  useful  in  the  treatment  of  sensitive 
dentin,  and  in  cavities  of  teeth  with  hyperaemia  of  the  pulp.  It 
is  tolerated  in  both  of  these  conditions  better  than  any  other 
filling  material,  and,  if  well  put  in,  will  generally  stand  long 
enough  to  accomplish  good  results.  But  to  do  well  in  either  of 
these  classes  of  cases,  it  must  be  made  to  cohere  to  the 
walls  of  the  cavity.  Otherwise  it  is  liable  on  account  of  its 
softness  to  slight  movement  in  the  ca\ity,  and  to  admit  moisture. 
In  that  case  the  condition,  especially  of  sensitive  dentin,  is  liable 
to  be  made  worse  instead  of  better. 

Exposure  and   Removal  of  the  Dental  Pulp. 

Exposure  of  the  dental  pulp. — The  pulp  of  a  tooth  may 
be  found  exposed  by  caries  so  that  it  lies  naked  and  in  view  ; 
it  may  have  been  reached  by  the  extension  of  caries  but  remain 
covered  by  a  softened  carious  mass  of  dentin  ;  it  may  become 
exposed  by  accident  during  the  preparation  of  a  carious  cavity  ; 
the  conditions  may  require  that  an  intentional  exposure  be  made 
through  a  carious  cavity  that  has  nearly  reached  the  pulp,  or 
that  an  intentional  exposure  be  made,  there  being  no  carious 
cavity. 

The  first  and  second  cases  are  so  similar  that  they  may  be 
treated  of  together,  only  noticing  differences  of  manipulation  as 
they  occur.  In  both,  the  supposition  is  that  the  pulp  is  to  be 
destroyed  and  removed.  In  the  first  procedure  the  problem  is 
the  preparation  of  the  cavity  for  the  treatment  of  the  exposed 
pul[>,  and  with  the  least  pain  and  inconvenience  to  the  patient. 

The  requirement  is  that  the  cavity  be  opened  by  the  removal 


138       THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

of  all  overhanging  enamel  and  that  the  surrounding  walls  be 
freed  from  carious  material,  perfectly  cleaned  to  solid  dentin, 
and  cut  to  a  form  that  will  certainly  retain  a  temporary  filling  for 
the  purpose  of  sealing  in  applications  that  may  be  required  in 
the  treatment  of  the  pulp.  It  is  not  required  here  that  the 
cavity  be  cut  to  the  full  outline  form,  as  it  will  be  prepared  to 
receive  the  permanent  filling  later  ;  nor  that  permanent  anchor- 
ages be  provided  ;  but  it  is  required  that  good  and  sufficient 
anchorage  be  provided  for  a  temporary  gutta-percha  filling 
against  good  clean  surrounding  walls  in  every  part.  It  should 
be  opened  sufficiently  wide  to  admit  of  the  free  and  easy  appli- 
cation of  instruments  for  the  exposure  of  the  pulp.  In  doing 
this  especial  care  should  be  taken  that  the  instruments  used  be 
not  directed  toward  the  pulp  of  the  tooth  and  that  it  be  not 
interfered  with  in  any  way  until  after  the  surrounding  walls  are 
clean  and  solid  in  every  direction.  This  excavation  is  to  be 
done  upon  the  principles  already  laid  down  for  the  excavation 
of  cavities  in  the  class  to  which  the  case  in  hand  belongs.  If 
the  rubber  dam  has  not  been  placed  at  the  beginning,  it  should 
be  placed  now  and  every  preparation  made  for  the  best  possible 
view  of  the  deeper  parts  of  the  cavity.  The  next  step  is  the 
removal  of  the  carious  material  from  the  deeper  parts  of  the 
cavity  —  the  axial  or  pulpal  wall  —  and  from  about  the  expo- 
sure. In  case  the  exposure  is  large  and  the  pulp  is  already 
laid  bare,  this  need  not  be  very  perfectly  done  at  first,  the  ne- 
cessity being  that  applications  can  be  laid  directly  upon  the  pulp 
tissue  and  perfectly  sealed  in  place  by  a  temporary  filling.  In 
case  the  pulp  is  covered  with  carious  material  only  this 
should  be  removed  and  the  tissue  of  the  pulp  laid  bare. 
In  every  position  this  should  be  done  with  the  broadest  cutting 
instrument  that  is  applicable  to  the  position,  usually  with  the 
spoons.  One  should  never  undertake  to  remove  softened  mate- 
rial from  over  a  pulp  with  an  instrument  so  small  that  it  is  liable  to 
penetrate  through  the  opening  into  the  pulp  chamber,  lacerate 
the  pulp  tissue,  and  inflict  unnecessary  pain.  This  should  be 
taken  as  a  principle  controlling  every  procedure  in  this  class  of 
cases,  and  the  operator  should  see  to  it  particularly  that  the  cav- 
ity be  so  opened  and  prepared  that  broad  points  may  be  used 
with  facility.  When  these  preparations  have  been  made,  if  the  case 
be  other  than  a  proximate  cavity  in  the  incisors,  take  the  spoon 


EXPOSURE    AND    REMOVAL    OF    THE    DENTAL    PULP.        139 

20-9-12,  and  having  determined  the  best  direction  in  which  to 
make  a  sweeping  cut,  start  its  edge  carefully  under  the  carious 
mass  close  against  one  of  the  walls  of  the  cavity  and,  with  a  strong 
thrust  in  a  curved  direction,  carry  it  across  the  other  side,  cut- 
ting at  once  to  the  full  depth  of  the  softened  dentin,  and  if  pos- 
sible remove  the  whole  mass  at  the  single  cut,  laying  the 
pulp  bare.  This  should  be  carefully  planned  and  firmly  exe- 
cuted. If  the  cut  should  be  through  the  superficial  portions  of 
the  pulp,  excising  a  portion  of  the  tissue,  it  is  just  as  well,  for 
when  the  hemorrhage  has  ceased  we  are  sure  of  the  best  condi- 
tion for  the  absorption  of  remedies  for  destroying  it,  whether 
this  be  done  by  the  application  of  the  arsenic  or  by  the  use  of 
cocaine  under  pressure.  In  some  broad  cavities  in  which  it  may 
seem  that  the  carious  mass  is  too  broad  to  be  removed  at  a  single 
cut,  one  or  more  preparatory  cuts  may  be  made  to  either  side, 
avoiding  the  pulp,  before  making  the  principal  cut  for  its 
exposure. 

An  exposure  of  the  pulp  made  in  this  way  is  usually  not  very 
painful,  and  even  if  it  be  very  sensitive,  the  duration  of  the  pain 
is  reduced  to  the  shortest  limit. 

In  proximate  cavities  in  the  incisors  the  spoons  20-9-12  can 
not  generally  be  used  for  want  of  room.  Much  oftener  the 
spoons  15-8-12  or  the  discoid  are  applicable.  In  these  cavities 
the  most  desirable  direction  for  the  final  cut  for  exposing  the 
pulp  is  from  the  gingival  toward  the  incisal  directly  over  the 
pulp.  In  these  cases  the  opening  into  the  pulp  is  apt  to  be  long 
inciso-gingivally,  and  if  the  broad  cutting  edge  can  be  placed  at 
right  angles  to  this  it  is  much  safer  against  dropping  into  the 
pulp  chamber  and  producing  unnecessary  laceration  of  the  sen- 
sitive tissues.  By  proceeding  carefully  this  position  or  an  angle 
closely  proximating  it  can  often  be  obtained,  and  then  the 
exposure  is  made  with  safety  ;  a  discoid  15  is  really  the  best 
instrument  for  the  purpose  in  this  position.  By  working  with 
care  the  exposure  maybe  made  with  hatchet  12-5-12,  cutting 
from  labial  to  lingual,  but  with  much  more  danger  of  inflicting 
severe  pain. 

Destroying  the  dental  pulp,—  When  the  pulp  has  been 
fully  exfjoscd,  the  cavity  should  be  ready  for  the  ap[)lication  to 
the  pulp  without  further  [m.-paration.  If  it  is  to  be  destroyed  by 
arsenic,  cut  a  piece  of  ordinary  writing  paper  of  such  size  and 


140       THE   TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

form  that  it  may  be  easily  so  laid  in  the  cavity  as  to  cover  the 
exposure,  and  try  it  in  place.  Then  the  walls  of  the  cavity 
should  be  moistened  with  eucalyptol  or  oil  of  cajuput,  to  pre- 
pare them  for  receiving  a  gutta-percha  filling,  and  any  excess  of 
oil  removed.  Then  place  a  small,  but  sufficient  amount  of 
arsenical  paste  upon  this  paper,  and  apply  it  directly  to  the 
exposure,  and  press  it  gently  in  place  ;  see  to  it  carefully  that 
there  is  not  so  much  of  the  paste  that  it  will  run  out  around  the 
margins  of  the  paper,  and  be  in  danger  of  smearing  the  walls  of 
the  cavity,  and  possibly  getting  out  toward  the  gingival  margin 
of  proximate  cavities,  for  in  this  case  there  will  be  danger  of 
arsenical  poisoning  of  gum  tissues.  Place  over  this  a  gutta- 
percha filling,  using  especial  care  not  to  make  unnecessary 
pressure  over  the  exposure  of  the  pulp  that  will  cause  compres- 
sion and  pain.  This  gutta-percha  filling  should  be  as  perfect  in 
its  adaptation  to  the  cavity  walls  as  it  is  possible  to  make  it,  in 
order  that  there  may  be  no  leakage  of  the  arsenic  outward  to 
poison  the  surrounding  tissues,  or  of  moisture  from  without 
inward  to  interfere  with  the  action  of  the  drug.  Another  impor- 
tant care  should  be  that  in  proximate  cavities  no  overplus  of 
gutta-percha  be  allowed  to  infringe  upon  the  gum  septum  and 
cause  absorption.  Overplus  in  this  direction  is  readily  avoided 
by  placing  any  suitable  instrument  between  the  teeth  at  the  gin- 
gival, such  as  the  shaft  of  hoe  8-3-6,  and  making  the  gutta- 
percha filling  against  that,  and  afterward  removing  the  instru- 
ment. This  gives  room  for  the  gum  septum,  and  yet  allows  the 
temporary  filling  to  be  placed  firmly  against  the  proximating 
tooth.  Finally,  the  filling  must  be  so  finished  as  not  to  give  the 
patient  annoyance,  after  which  the  patient  may  be  discharged  for 
forty-eight  hours,  or  until  the  arsenic  has  acted. 

Anaesthetizing  the  dental  pulp. —  If  it  has  been  decided 
to  anaesthetize  the  pulp  with  cocaine  under  pressure,  the  opening 
into  the  pulp  must  be  free  and  large,  and  the  position  such  that 
the  after  manipulation  can  be  readily  done.  The  surrounding 
walls  must  be  sufficient  so  that  the  drug  may  be  readily  confined 
under  pressure,  and  the  access  fairly  direct.  Otherwise  arsenic 
should  be  used. 

When  the  cavity  has  been  fully  prepared  —  an  occusal  cav- 
ity in  an  upper  first  molar  for  example  —  a  sufficient  amount  of 
cocaine  crystals  should  be  dissolved  in  a  few  drops  of  water  in  a 


EXPOSURE  AND  REMOVAL  OF  THE  DENTAL  PULP.   141 

capsule  (always  made  fresh  for  each  case),  and  a  small  pellet  of 
cotton  saturated  with  this  solution  is  placed  in  the  cavity  upon 
the  exposed  pulp.  Over  this  place  a  pellet  of  soft,  or  unvulcan- 
ized,  vulcanite  rubber  that  will  completely  fill  the  orifice  of  the 
cavity  and  prevent  the  escape  of  the  solution.  Upon  this  make 
pressure  with  a  broad-faced  amalgam  plugger.  The  pressure 
should  be  gentle  at  first,  and  be  gradually  increased  as  the  pain 
is  relieved,  watching  for  evidence  of  pain  in  the  countenance  of 
the  patient,  until  very  heavy  pressure  can  be  made.  This  should 
be  maintained  for  several  minutes.  Then  if  all  has  gone  well 
the  rubber  and  the  cotton  may  be  removed,  and  the  pulp  will 
be  found  insensible  and  its  removal  may  be  proceeded  with.* 

In  anaesthetizing  the  pulp  in  this  way  notice  particularly  that 
the  cavity  must  be  so  stopped  with  the  soft  rubber  as  to  prevent 
the  escape  of  the  solution  along  the  cavity  walls,  otherwise  the 
pressure  will  fail  to  force  the  drug  into  the  pulp  tissue  and  the 
anaesthesia  will  fail.  This  is  fairly  easy  of  accomplishment  in 
the  cavity  named  above  and  those  of  similar  form  and  situation. 
But  in  proximate  cavities  it  is  often  much  more  difficult  to  so 
place  the  rubber  that  it  will  successfully  stop  the  orifice  of  the 
cavity  and  prevent  the  escape  of  the  fluid.  In  the  molars  and 
bicuspids  this  may  be  successfully  done  by  first  placing  a  properly 
formed  piece  of  rubber  against  the  proximating  surface  of  the 
adjacent  tooth  and  forcing  it  against  the  gingival  wall  of  the 
cavity,  and  then  doubling  it  over  the  occlusal  portion  so  as  to 
close  that  also,  and  then  applying  pressure  with  a  broad  instru- 
ment point  selected  to  fit  the  cavity  to  the  best  advantage.  As 
one  becomes  expert  in  this,  most  cavities  may  be  so  handled  as 
to  successfully  produce  anaesthesia  of  the  pulp. 

Opening  the  pulp  chamber  preparatory  to  removal 
of  the  pulp. — When  the  pulp  has  been  destroyed  by  arsenic, 
the  procedure  when  the  patient  has  returned  for  the  next  sitting 
is  first  to  adjust  the  rubber  dam.  In  proximate  cavities  in  which 
the  gutta-percha  filling  has  been  placed  firmly  against  the 
proximating  tooth,  the  filling  must  first  be  cut  through  with  a 
Koeber  saw,  or  trimmed  away  with  a  sharp  finishing  knife  in 
order  to  allow  the  rubber  dam  to  pass.  When  the  dam  is  in 
position  sterilize  the  field  of  operation  by  mopping  the  teeth 
included,  their  interproximate  spaces  and  the  adjacent  rubber 

*  Prof.  A.  H.  Peck's  Lectures,  1899. 


142       THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH, 

with  1-2-3,  oil  of  cloves  or  oil  of  cassia,  and  then  drying  them 
off  with  absorbent  cotton.  Then  the  gutta-percha  filling  may- 
be softened  by  warming  a  burnisher  and  passing  the  hot  point 
into  it,  and  holding  it  for  a  moment  to  allow  the  general  softening 
of  the  gutta-percha,  when  it  may  be  lifted  out. 

The  cavity  is  now  freed  from  the  arsenic  paste  and  washed 
out  with  the  antiseptic  and  dried.  It  is  now  ready  to  proceed 
with  the  opening  of  the  pulp  chamber.  In  case  the  pulp  has 
been  anaesthetized  with  cocaine,  the  rubber  dam  will  be  in  place 
and  ready  for  the  opening  of  the  pulp  chamber  so  that  from  this 
time  the  procedures  in  the  two  cases  will  be  similar.  In  either 
case  the  pulp  should  first  be  pricked  cautiously  with  a  very  fine 
broach,  to  be  sure  that  it  has  lost  its  sensibility,  for  sometimes 
there  is  a  failure  in  either  way  of  operating.  Having  determined 
that  the  conditions  are  favorable  for  removal  of  the  pulp,  the  first 
operation  is  the  opening  of  the  pulp  chamber.  In  the  bicuspids 
and  molars  this  consists  in  the  removal  of  the  entire  roof,  or  den- 
tinal covering,  and  the  manner  of  doing  this  will  depend  much 
upon  the  extent  and  the  location  of  the  decay. 

In  occlusal  cavities  in  the  molars  in  which  the  decay  is 
large,  often  the  hoe  6-2-23  can  be  slipped  into  the  opening  and 
the  roof  of  the  chamber  pulled  away,  uncovering  the  entire  pulp. 
But  when  the  dentinal  covering  is  strong,  as  is  usually  the  case 
when  the  opening  is  only  the  exposure  of  one  of  the  horns  of  the 
pulp,  the  better  way  is  to  enlarge  the  opening  with  a  small  fissure 
bur.  This  is  passed  into  the  pulp  chamber  through  the  orifice 
of  the  exposure,  and  when  the  operator  is  sufficiently  sure  in  his 
knowledge  of  the  anatomy,  he  may  cut  around  the  pulp  chamber 
parallel  with  its  axial  walls  and  remove  the  covering  in  a  single 
piece.  Otherwise  the  opening  may  be  enlarged  by  carrying  the 
bur  laterally  toward  the  central  portion  of  the  covering  of  the 
chamber  and  then  carrying  it  around  in  a  circle.  Then  hoe 
6-2-23  may  be  passed  into  the  opening  and  its  blade  turned 
under  the  roof  covering  the  pulp,  the  overhang  determined,  and 
the  cutting  directed,  until  the  whole  extent  of  the  chamber  is 
uncovered  ;  no  overhang  should  be  left  at  any  point.  In  this 
cutting  the  greatest  care  should  be  taken  that  the  bur  be  not 
pressed  onto  the  floor  of  the  chamber  and  its  form  marred  by  cut- 
ting into  it.  When  the  whole  of  the  roof  has  been  removed,  it  is 
generally  best  to  enlarge  somewhat  toward  the   mesio-buccal 


EXPOSURE    AND    REMOVAL   OF   THE    DENTAL    PULP.        143 

angle  in  order  to  better  reach  the  mesio-buccal  root  canal.  This 
may  be  done  most  readily  and  in  the  best  form  by  a  scraping 
movement  with  the  cleoid.  The  case  is  now  ready  for  the 
removal  of  the  pulp.  Incidentally  much  of  the  tissue  of  the 
bulb  of  the  pulp,  possibly  all  of  it,  will  have  been  removed  in 
doing  this  cutting,  but  no  attempt  should  be  made  to  remove 
the  pulp  from  the  canals  until  this  cutting  is  satisfactorily  com- 
pleted. 

In  many  cases  after  the  first  opening  has  been  made  the  roof 
of  the  pulp  chamber  can  be  cut  away  quicker  and  much  more 
satisfactorily  with  the  chisel  and  mallet. 

If  the  exposure  is  from  a  mesial  cavity  the  cutting  will 
be,  of  course,  to  the  distal  and  often  will  involve  the  removal  of 
the  middle  third  of  the  occlusal  surface  with  the  whole  of  the 
dentin  intervening  between  it  and  the  pulp.  If  a  distal  cavity, 
the  middle  third  bucco-lingually  of  the  occlusal  surface  with  the 
intervening  dentin  should  at  once  be  removed  to  a  point  well 
toward  the  mesial  marginal  ridge. 

In  the  bicuspids  the  exposures  are  almost  uniformly  from 
cavities  in  the  proximate  surfaces,  and  the  chambers  are  broad 
bucco-lingually.  The  cutting  for  the  opening  of  the  chambers 
must  be  directed  first  to  the  central  part  of  the  crown,  but  later 
broadened  from  buccal  to  lingual  ;  for  the  horns  of  the  pulp, 
when  long,  in  these  teeth  spread  out  toward  the  points  of  the 
cusps.  These  should  be  fully  opened  into  so  that  they  may  be 
cleaned,  also  the  root  canals  in  these  teeth,  especially  in  upper 
first  bicuspids,  are  given  off  from  the  extreme  buccal  and 
extreme  lingual  portions  of  the  chamber,  and  unless  this  cutting 
is  broad  in  this  direction,  the  broach  will  not  have  direct  entrance 
into  them. 

In  the  incisors  and  cuspids  exposures  are  generally  from 
proximate  cavities.  In  opening  these  for  the  removal  of  the 
pulp,  the  orifice  of  the  exposure  should  be  first  extended  to  the 
gingival  wall  of  the  cavity,  and.  to  the  full  breadth  of  the  cham- 
ber. The  approach  should  be  carefully  considered.  Generally 
a  broach  will  not  readily  slide  into  the  canal  without  being  bent 
more  or  less.  This  is  unfavorable,  and  a  better  approach  must 
be  made.  Generally  when  a  cavity  is  so  large  that  the  pulp  has 
been  reached,  the  lingual  wall  should  be  cut  away,  and  this  will 
improve  the  approach,  the  instrument  being  passed  to  the  lingual 


144       THE    TECHNICAL    PROCEDURES    IN   FILLING   TEETH. 

of  the  incisal  edge  of  the  tooth  ;  rarely  the  labial  wall  should  be 
cut  away.  Then,  to  improve  the  approach  still  more,  take  a 
small  fissure  bur  in  the  engine,  and  approaching  the  canal  from 
the  direction  in  which  a  broach  would  be  introduced,  pass  it  into 
the  canal,  and  cut  by  lateral  pressure  broadening  the  canal  in  a 
direction  to  straighten  the  approach.  This  cutting  will  be 
toward  the  disto-lingual  if  a  distal  cavity,  or  mesio-lingual  if  a 
mesial  cavity,  if  the  approach  is  to  the  lingual  of  the  incisal 
edge.  From  whatever  the  direction  of  the  approach,  the  cutting 
is  to  be  so  directed  that  the  broadening  of  the  coronal  portion 
of  the  canal  will  straighten  it.  In  this  cutting  special  care 
should  be  had  that  the  end  of  the  bur  should  not  cut  the  oppo- 
site side  of  the  canal  and  roughen  it,  for  if  it  should,  the  point 
of  an  instrument  will  be  catching  in  the  rough  points  at  every 
effort  to  introduce  it  into  the  canal.  By  this  cutting  the  curve 
of  the  instruments  introduced  into  the  canal  for  the  removal  of 
the  pulp,  or  for  filling  the  canal,  will  be  much  less  abrupt,  and 
these  operations  can  be  done  more  perfectly. 

It  is  particularly  desirable  that  all  cutting  in  opening  the  pulp 
chamber  be  completed,  and  the  cavity  cleaned  of  chips  or  cut- 
tings before  the  pulp  is  removed  from  the  root  canals.  Often 
these  cuttings  will  fall  into  a  small  canal,  and  an  instrument 
thrust  will  so  fasten  them'  as  to  occlude  the  canal.  If  in  any 
case  it  should  become  necessary  to  do  more  cutting  after  remov- 
ing the  pulp  from  one  root  canal  in  order  to  gain  access  to 
another,  a  wisp  of  cotton  to  catch  any  chips  should  first  be 
placed  in  the  open  canal. 

Removal  of  the  Pulp. 

The  instruments  used  for  removing  the  pulp  from  the 
canals  are  the  barbed  broach  and  the  smooth  broach.  Gen- 
erally the  barbed  broach  should  be  used  first.  Usually  the  bulb 
of  the  pulp  will  have  been  removed  during  the  opening  of  the 
pulp  chamber,  and  the  broach  selected  should  be  suited  in  size 
to  the  canal.  Test  the  broach  before  using  it  by  taking  the 
point  on  the  finger  and  bending  it.  See  that  it  bends  in  a 
regular  curve.  Occasionally  in  cutting  the  barbs  the  shaft  is  cut 
too  deeply  at  some  point,  which  will  cause  it  to  break  easily  — 
such  a  broach  should  be  discarded.     The  broach  should  be  held 


EXPOSURE   AND    REMOVAL    OF    THE    DENTAL    PULP.        1-45 

in  a  light  handle,  but  may  be  used  without.  Just  before 
introducing  the  broach  dip  it  into  a  good  antiseptic,  pref- 
erably 1-2-3,  or  oil  of  cloves.  This  should  never  be  neglected, 
for  the  broaches  are  liable  to  carry  micro-organisms  into  the 
canal  and  infect  it.  Now  pass  the  broach  into  the  canal,  direct- 
ing it  against  one  of  the  walls,  so  that  it  will  pass  in  beside  the 
pulp  tissue  rather  than  through  it.  Generally  the  point  should 
be  pushed  to  the  apical  foramen  and  then,  if  it  is  felt  to  be  held 
tightly  in  the  apical  end  of  the  canal,  withdraw  it  until  it  is  felt 
to  be  loose.  Now  rotate  the  broach  lightly,  moving  it  slightly 
back  and  forth  to  be  sure  that  the  whole  length  is  rotating  and 
not  being  held  in  some  curved  part  of  the  canal  which  would  be 
liable  to  break  the  broach.  The  rotation  should  not  exceed  one 
turn,  then  withdraw  it.  In  a  good  many  cases  the  entire  con- 
tents of  the  canal  will  be  brought  away  with  the  first  effort.  If 
not,  the  movement  is  repeated.  Often  the  tissue  of  the  pulp 
will  break  up  into  shreds  and  be  but  partially  removed.  In  this 
case  the  smooth  broach  with  cotton  should  be  used.  For 
preparing  this  the  fingers  should  be  disinfected  by  taking  a  bit 
of  cotton  moistened  with  the  disinfecting  agent  used,  and  rolling 
it  between  the  fingers  and  thumb.  Then  take  a  small  bit  of 
absorbent  cotton  and  pull  it  between  the  fingers  of  the  two 
hands  until  a  small  shred  is  formed  containing  but  a  few  parallel 
fibers.  Take  one  end  of  this  between  the  forefinger  and  thumb 
of  the  right  hand  and  grasp  with  it  the  broach  at  midlength,  or 
with  the  cotton  wisp  extending  slightly  past  its  point.  With  the 
left  hand  grasp  the  other  end  of  the  cotton  wisp  and  the  point 
of  the  broach  together  and  rotate  the  broach  in  the  fingers  of 
the  right  hand  until  the  cotton  is  wrapped  firmly  upon  its  shaft. 
When  this  is  properly  done  the  cotton  will  cling  firmly  to  the 
broach,  and  is  not  likely  to  be  lost  in  the  canal.  With  the 
broach  thus  armed,  dip  it  first  in  the  antiseptic  and  then  pass  it 
into  the  canal,  slightly  rotating  back  and  forth.  When  the  full 
depth  has  been  reached,  turn  the  broach  fully  upon  its  axis  and 
withdraw  it  while  in  rotation.  Generally  the  shreds  of  the  pulp 
will  become  entangled  in  the  cotton  and  be  brought  away.  This 
should  be  repeated  until  satisfied  that  all  tissue  has  been  removed 
from  the  canal  to  the  apex. 

.Students  often   have  difficulty  in  finding  the  canals  in  the 
molar  teeth.      .Specific  directions  for  approaching  them  are  given 
10 


146       THE    TECHNICAL    PROCEDURES    IN    FILLING   TEETH. 

in  the  anatomy.*  Difficulty  of  this  kind  should  not  occur 
except  in  abnormal  cases,  and  when  they  do,  it  is  generally 
because  the  floors  of  the  pulp  chambers  have  been  mutilated 
with  burs,  and  the  openings  of  the  canals  filled  with  chips. 
This  should  never  be  done  ;  burs  should  not  be  used  in  the  floor 
of  the  pulp  chamber. 

No  specific  directions  can  be  given  for  abnormal  cases.  When 
the  pulp  chamber  is  filled  with  secondary  deposits,  the  effort 
should  be  directed  to  the  removal  of  these,  preserving  the  out- 
lines of  the  pulp  chamber.  When  the  pulp  chamber  is  much 
narrowed  by  secondary  dentin  deposited  upon  its  walls,  the 
openings  into  the  canals  should  be  found  before  any  cutting  is 
done,  and  then  the  cutting  carefully  directed  to  straightening 
them.  In  most  instances  this  is  done  best  with  the  barbed 
broach.  All  small  tortuous  canals  should  be  enlarged  and 
straightened  with  the  barbed  broach.  To  do  this,  cause  the 
broach  to  enter  the  canal  as  far  as  possible  and  withdraw  it.  The 
barbs  will  impinge  upon  the  walls  and  cut  away  the  dentin. 
Repeat  this,  pressing  the  broach  in  a  direction  that  will  tend  to 
straighten  the  canal.  By  repetitions  of  the  movement,  the  canal 
that  can  be  entered  by  the  smallest  broach  can  soon  be  enlarged 
sufficiently  for  filling.  Generally  partial  occlusions  of  canals  are 
confined  to  or  near  their  pulpal  ends,  and  where  this  has  been 
straightened  up,  the  broach  will  pass  to  the  apex.  In  elderly 
people  certain  canals  are  often  too  small  for  successful  cleaning 
and  filling.  In  cases  in  which  there  has  been  much  wearing 
away  of  the  teeth,  the  pulp  chambers  and  the  pulpal  ends  of  the 
root  canals  are  apt  to  be  much  narrowed  by  secondary  dentin. 
This  applies  to  all  of  the  teeth  in  the  mouth,  i.  e.,  to  any  that 
have,  from  any  cause,  not  been  worn  away  the  same  as  those 
that  are  worn. 

When  the  root  canals  have  been  cleaned,  it  is  generally  neces- 
sary that  a  dressing  be  laid  in  the  canals  and  the  cavity  sealed 
with  a  gutta-percha  filling  until  a  future  time.  For  this  purpose 
a  wisp  of  cotton  should  be  formed  with  its  fibers  mostly  parallel, 
and  the  end  of  this  caught  with  the  point  of  the  broach  with  the 
thumb  and  finger  of  the  left  hand  and  the  broach  rotated  with 
the  right  hand,  while  the  fingers  of  the  left  roll  the  cotton  on  its 


*  Black's  Dental  Anatomy.    For  upper  molars,  paragraphs  173  to  178  inclusive;   for 
lower  molars,  paragraphs  180  to  185  inclusive,  to  which  the  reader  is  referred. 


EXPOSURE    AND    REMOVAL    OF    THE    DENTAL    PULP.        147 

end.  In  this  way  the  cotton  is  rolled  on  the  broach  in  such  a 
way  that  it  will  not  slip  backward  on  the  broach  and  can  be  car- 
ried to  the  apical  end  of  the  canal  ;  and  when  the  broach  is 
withdrawn  the  cotton  will  remain  in  the  canal.  This  is  now 
saturated  with  the  dressing,  or  drug  indicated,  and  laid  in  the 
canal.  One  end  of  the  cotton  wisp  should  project  into  the  pulp 
chamber  in  order  that  it  may  readily  be  removed  at  another  sit- 
ting, and  the  cavity  sealed  with  a  gutta-percha  filling. 

Rule  :  In  no  case  should  the  saliva  be  allowed  to 
enter  a  root  canal  after  the  pulp  has  been  removed.  At 
any  future  sitting  the  rubber  dam  must  be  applied  and  the 
included  region  disinfected  before  the  gutta-percha  filling  is 
removed.  Any  neglect  of  this  precaution  is  apt  to  result  in 
alveolar  abscess. 

In  cases  of  dead  pulps,  pulps  in  a  state  of  decomposition, 
empty  root  canals,  alveolar  abscesses,  etc.,  the  technical  proc- 
esses of  cleaning  the  canals  are  not  essentially  different  from 
those  described,  though  they  may  require  radically  different 
medicinal  treatment.  This  latter  is  not  within  the  province  of 
this  book. 

Opening  the  Pulp  Chamber  in  Sound  Teeth. 

Frequently  it  is  necessary  to  open  the  pulp  chamber  of  teeth 
that  are  sound,  or  have  fillings  previously  inserted  that  it  is  not 
desirable  to  remove.  The  pulp  may  be  dead  or  in  such  a  con- 
dition of  disease  that  it  should  be  removed.  In  these  cases  it 
becomes  necessary  to  cut  from  the  surface  of  the  tooth  or  through 
the  filling.  In  case  of  the  incisors  or  cuspids  the  best  place 
to  enter  the  pulp  chamber  is  through  the  central  portion  of  the 
lingual  surface.  For  this  purpose  a  bibeveled  drill,  one  milli- 
meter in  diameter,  should  be  first  used.  With  this  the  enamel 
should  be  penetrated  and  the  drill  forced  a  little  distance  into 
the  dentin.  Then  this  opening  should  be  considerably  enlarged 
by  a  larger  drill  or  a  round  bur.  Then  the  small  drill  should  be 
forced  carefiilly  into  the  pulp  chamber.  If  the  pulp  is  alive  and 
sensitive,  it  should  now  be  destroyed.  Afterward  the  complete 
opening  of  the  chamber  may  be  jjroceeded  with.  If  the  pulp 
is  dead,  the  fiirther  opening  of  the  chamber  may  be  done  at 
once. 

In  cutting  into  the  pulp  chamber  the  drill  has  entered  from 


148       THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

the  lingual  at  a  considerable  inclination,  and  it  is  now  necessary 
to  make  the  opening  as  near  parallel  with  the  length  of  the  pulp 
canal  as  practicable.  To  do  this  use  a  fissure  bur,  pass  its  end 
into  the  pulp  chamber  and  bring  the  hand-piece  slowly  parallel 
with  the  long  axis  of  the  tooth,  cutting  mostly  from  the  incisal 
wall  of  the  opening  first  made,  but  also  cutting  some  from  the 
distal  wall  of  the  pulp  chamber.  This  cutting  should  be  suf- 
ficient to  admit  a  broach  to  the  full  length  of  the  canal,  with 
very  little  bending.  The  cleaning  and  treatment  of  the  canal 
can  then  be  proceeded  with. 

Generally,  when  incisors  have  proximate  fillings  that  are 
good,  the  opening  into  the  pulp  should  be  made  from  the  lin- 
gual, without  disturbing  the  fillings.  If,  however,  there  is  reason 
for  removing  a  proximate  filling,  the  pulp  chamber  should  be 
opened  through  the  cavity. 

In  case  of  bicuspids  and  molars  the  opening  should  be 
made  through  the  occlusal  surface.  In  bicuspids  the  mesial  pit 
should  be  chosen.  In  molars  it  is  generally  much  easier  to 
penetrate  the  enamel  through  the  pit  in  the  central  fossa.  In 
this  case,  as  soon  as  the  dentin  has  been  entered,  it  is  best  to 
introduce  a  small  inverted  cone  bur,  and  cut  a  slot  to  the  mesial, 
inclining  to  the  buccal,  as  far  as  the  mesial  marginal  ridge,  and 
chip  the  enamel  from  its  margins.  The  length  of  this  toward 
the  mesial  will  depend  on  the  position  of  the  tooth  and  the  incli- 
nation of  the  hand-piece  in  drilling  through  the  dentin.  The 
dentin  is  thick,  and  in  passing  through  it,  this  inclination  will 
often  carry  the  hole  considerably  to  the  distal.  Therefore,  in 
beginning  again  with  the  drill  it  should  be  set  sufficiently  to  the 
mesial  so  that  it  will  strike  the  pulp  chamber  centrally,  or  to  the 
mesial  of  its  center.  In  drilling  through  the  dentin  the  small 
drill  (one  millimeter  in  diameter)  should  first  be  made  to  pene- 
trate a  little,  and  then  the  hole  enlarged,  then  drilled  deeper  and 
enlarged,  until  the  dentin  has  been  cut  through.  If  the  pulp  is 
alive  and  sensitive,  it  should  now  be  destroyed  ;  if  dead,  the 
opening  may  at  once  be  so  enlarged  as  to  remove  the  entire 
roof  of  the  pulp  chamber,  and  the  treatment  of  the  canals  pro- 
ceeded with.  Never  undertake  to  treat  pulp  canals  through  a 
little  bit  of  an  opening. 

In  a  considerable  number  of  cases  it  is  necessary  to  open  the 
pulp  chambers  of  bicuspid  and  molar  teeth  that  have  been  filled. 


FILLING    ROOT    CANALS.  149 

If  the  fillings  are  good,  proceed  as  if  the  tooth  was  sound,  cut- 
ting through  the  filling,  or  through  the  dentin,  as  the  case 
demands.  If  there  is  reason  for  removing  the  filling,  do  so  at 
once,  and  open  the  pulp  chamber  through  the  cavity. 

Filling  Root  Canals. 

When  it  is  decided  that  the  conditions  are  right  for  filling  the 
root  canal,  or  canals  of  a  tooth,  the  rubber  dam  must  be  placed 
and  the  included  region  disinfected.  Then  if  a  treatment  has 
been  in  the  canal  the  gutta-percha  filling  and  the  dressing  is 
removed  and  a  critical  examination  made  as  to  its  condition.  If 
this  is  satisfactory,  first  see  that  the  canal  is  reasonably  dry, 
then  flood  it  with  eucalyptol  or  oil  of  cajuput,  liberally  applied 
upon  a  wisp  of  cotton  wrapped  upon  a  broach,  and  dry  out  the 
excess  with  a  fresh  wisp  of  cotton  that  has  first  been  dipped  in 
the  oil  and  well  squeezed  out  with  another  wisp  of  cotton.  Try 
the  sizes  of  the  root  canal  pluggers  in  the  canal,  always  washing 
the  point  with  an  antiseptic  first,  and  select  one  that  will 
pass  nearly,  but  not  quite,  to  the  apical  foramen.  Select  a 
gutta-percha  cone  and  cut  a  portion  of  it  about  three  or  four 
millimeters  long  of  the  size  which,  from  the  information  gained 
of  the  size  of  the  apical  end  of  the  canal,  will  be  sufficient  to  fully 
fill  the  opening  and  not  force  through  the  apical  end.  Warm  the 
point  of  the  root  plugger  selected,  and  holding  the  piece  of 
gutta-percha  cone  in  the  thumb  and  finger  of  the  left  hand,  bring 
its  point  quickly  in  contact  with  its  large  end,  and  hold  it  a 
moment,  or  until  the  gutta-percha  has  stuck  to  the  end  of  the 
instrument.  Dip  this  into  eucalyptol,  which  will  soften  the 
surface  of  the  gutta-percha  slightly;  convey  this  to  the  root  canal 
and  start  it  in  carefully,  and  carry  it  firmly  into  its  apical  end. 
On  withdrawing  the  root  plugger  the  gutta-percha  cone  will 
remain,  closing  the  apical  end  of  the  root.  Repeat  this  with 
other  bits  of  gutta-percha  cones  ;  cut  them  from  larger  parts  of 
the  cones  as  the  canal  is  filled  to  its  larger  portion  and  use  the 
larger  root  canal  plugger.  After  the  first  two  or  three  pieces 
the  subsequent  ones  may  be  slightly  softened  by  passing  them 
quickly  over  the  flame  of  the  annealing  lamp  and  directly  into 
the  canal.      Continue  this  until  the  canal  is  full. 

This  plan  of  filling  root  canals  is  applicable  to  all  except  the 
very  smallest,  and  to  all  positions.      In  some  of  the  smaller  ones 


150       THE    TECHNICAL    PROCEDURES    IN    FILLING    TEETH. 

it  is  necessary  to  make  a  special  root  canal  plugger  for  the  case 
by  cutting  ofif  the  barbed  portion  of  a  Donaldson  broach  of  a 
suitable  size  and  squaring  its  end  on  the  stone. 

Rationale  of  this  procedure. —  By  flooding  the  root  canal 
with  eucalyptol  or  oil  of  cajuput  the  moisture  is  effectually 
removed.  The  oils  have  a  greater  affinity  or  attraction  for  the 
dentin  than  the  moisture  and  displace  it.  These  oils  dissolve 
gutta-percha  slightly,  and  the  little  remaining  serves  to  stick 
the  gutta-percha  firmly  to  the  walls  of  the  canal.  By  putting 
in  the  gutta-percha  in  small  pieces  an  opportunity  is  given  to 
pack  every  portion  of  the  canal  and  all  of  its  irregularities  full. 

In  filling  root  canals  that  are  very  large  at  the  apical  end,  as 
in  young  persons,  care  must  be  exercised  that  the  first  cone 
selected  is  not  so  small  that  it  could  be  forced  through  into  the 
apical  space.  In  very  small  canals,  in  which  there  is  much 
doubt  of  being  able  to  reach  the  apical  end,  chloro-percha  * 
should  be  pumped  into  them,  filling  them  as  completely  as  pos- 
sible, and  then  a  small  solid  cone  forced  in.  This  pumping  in 
of  chloro-percha  is  done  by  wrapping  three  or  four  fibers  of  cot- 
ton firmly  on  a  small  broach,  dipping  this  in  the  chloro-percha 
and  conveying  it  into  the  canal  and  pumping  it  back  and  forth, 
repeating  the  operation  until  the  canal  seems  to  be  well  filled. 
Then  thrust  a  root  canal  plugger  of  suitable  size  into  it  and 
force  out  some  of  the  gutta-percha  from  the  pulpal  end.  Then, 
having  a  suitable  gutta-percha  cone  prepared,  quickly  stick  it 
onto  the  plugger  point,  and  thrust  it  as  far  into  the  canal  as  pos- 
sible. Such  canals  may  not  always  be  perfectly  filled  by  this 
plan,  or  by  any  other.  But  in  each  case  the  best  effort  should 
be  made.  The  pulp  chamber  should  not  be  filled  with  gutta- 
percha. This  material  is  much  too  soft  to  serve  as  a  seat  for  a 
metallic  filling.  In  any  case  in  which  it  is  not  desirable  to  fill 
the  pulp  chamber  with  the  material  with  which  the  cavity  is  to 
be  filled,  oxy-phosphate  of  zinc  should  be  used. 

Horns  of  pulp  chambers. —  Attention  to  the  horns  of  pulp 
chambers  is  most  urgently  demanded  in  the  incisors,  cuspids  and 
bicuspids.  In  incisors  particularly,  exposures  of  the  pulp, 
whether  made  primarily  by  caries,  or  by  cutting  into  them,  are 
some  distance  from  the  incisal  end  of  the  pulp,  leaving  an  end 
protruding    into    the   incisal   end   of  the    crown  of  the  tooth. 

Gutta-percha  dissolved  in  chloroform. 


FILLING    ROOT    CANALS.  151 

Before  filling  the  cavity  this  must  be  looked  for  and  so  exposed 
that  every  part  of  it  is  cleaned  and  filled.  Any  neglect  in  this 
will  result  in  discoloration  of  the  tooth  by  the  decomposition  of 
the  debris  left  in  this  neglected  portion  of  the  pulp  chamber.  In 
cuspids  and  bicuspids  the  horns  of  the  pulp  are  often  long  and 
slender,  and  penetrate  far  toward  the  ends  of  the  cusps.  Unless 
these  are  thought  of,  and  especially  looked  for  and  cut  out, 
so  that  they  may  be  perfectly  filled,  discoloration  of  the  tooth  in 
some  degree  is  sure  to  occur. 


INDEX. 


PAGE. 

Amalgam  97 

filling  with 126 

instruments  for  filling  with 130 

kneading:  of 128 

packing,  fillings 129 

preparing  for  filling  with 128 

Amalgam  fillings,  discoloration  of 126 

finishing 130 

importance  of  separating  teeth  for '. 127 

placing  matrix  for 127 

removing  matrix  from   130 

where  admissible 127 

Annealing  gold : 101 

Application  of  force  in  filling  with  gold 105 

Bite,  strength  of  the 116 

Burs  in  cutting  out  grooves 35 

in  cutting  seats  and  steps 35 

in  making  extensions  for  prevention 36 

in  making  starting  points  tor  packing  gold 37 

in  squaring  out  angles  of  cavities 36 

Cavities,  beveling  cavo-surface  angle  of 23 

classification  of 8 

convenience  form  of 21 

distal,  in  lower  bicuspids,  preparation  of 91 

filling  distal,  in  bicuspids  and  molars 114 

filling  proximate,  in  incisors 114 

gingival  wall,  in  proximate 113 

in  incisors  and  cuspids,  general  observations  on  the  preparation  of 82 

in  proximate  surfaces  in  bicuspids  and  molars,  preparation  of 85 

nomenclature  of,  angles  of 13 

nomenclature  of,  internal  parts  of 10 

opening,  in  bicuspids  and  molars 86 

outline  form  of 20 

proximate  in  bicuspids  and  molars,  filling  with  combination  of  non-co- 
hesive and  cohesive  gold 115 

removing  carious  dentin  from 22 

resistance  form  of 20 

retention  form  of 21 

variations  in  preparation  of,  due  to  position 90 

Cavity  nomenclature 6 

nomenclature,  rule  for 6 

preparation,  general  principles  of 19 

preparation  defined 6 

toilet  of 23 

walls,  management  of  weak,  in  bicuspids  and  molars 92 

Cement,  filling  with  134 

Cements 131 

examination  of  physical  properties  of 132 

how  mixed ." 131,  132 

not  impervious  to  moisture 133 


154  INDEX. 

PAGE. 

Cements,  shrinkage  of 133 

"  solvent  action  of  oral  secretions  on 133 

"         use  of 133 

Clamps,  rubber  dam 50 

Classification  of  cavities 8 

Cotton,  wrapping  on  broach 145,  146 

Cutting  out  angles  of  cavities,  use  of  burs  in 36 

Cutting  out  grooves,  use  of  burs  in 35 

Cutting  seats  and  steps,  use  of  burs  in 35 

Cutting,  size  of  burs  for 34 

Dental  engine,  use  of 34 

Dental  instrument  gauge 26 

Divisions  of  the  surfaces  of  the  teeth  in  cavity  description 18 

Drills,  use  of 38 

Enamel 51 

histological  characters  of,  in  relation  to  preparation  of  cavities 52 

margins,  nomenclature  of 17 

"        rods,  how  to  study  the  inclinations  of 58 

rods,  inclinations  of 54 

"        walls,  finishing 23 

Excavation  of  cavities  by  classes 60 

Class  first 60 

variations  in 63 

second 69 

"  "        variations  in 76 

third 77 

"  "     general  observations  on 82 

fourth  83 

variations  in 85 

fifth 85 

"  "    variations  in 90 

Excavation  of  cavities,  order  of  procedure  in - 19 

Exposure  and  removal  of  the  dental  pulp 137 

Extension   for  prevention 9,  20,  70,    78 

"  "  "  in  bicuspids  and  molars 88 

"  "  "  use  of  burs  in  making , 36 

Filling  materials 97 

Filling  root  canals 149 

"  "  "       rationale  of  procedure  in 150 

"         "  "       with  large  apical  opening 150 

Filling,  starting  cohesive  gold 110 

with  amalgam 126 

"        with  cement 134 

"        with  cohesive  gold 105 

with  gold 102 

"        with  gutta-percha 135 

with  non-cohesive  gold 102 

Finishing  fillings 122 

"       buccal  and  lingual  embrasures 124 

"  "        gutta-percha 136 

"in  buccal  and  labial  cavities  123 

in  occlusal,  buccal  and  lingual  cavities 122 

obtaining  roundness  of  contact  point 125 

overtrimming  gingival  margin  in 128 

proximate 124 

"        use  of  burnisher  in 124 

use  of  corundum  stones  in 122 

"        use  of  disks  in 125 

use  of  rubber  disks  in 123 

use  of  tape  in 125 


INDEX. 


155 


PAGE. 

Finishing  fillings,  with  file-cut  finishing  files 125 

Force,  direction  of,  to  plane  of  walls  in  packing  gold Ill 

Forms  of  plugger  points ^^^ 

Forms  of  shanks  of  plugger  points 108 

Gold 97 

"      annealing   ^^^ 

■'      condensation  of  gases  on 9^ 

"      destroying  and  restoring  welding  property  of 100 

"      filling  with 102 

forms  of • "° 

"     welding  property  of ^^ 

Grasps,  rubber-dam ^^ 

Gutta-percha ^^^ 

filling  with .135 

finishing  fillings  of 136 

use  of  eucalyptol  in  filling  with 135 

Incisal  step . . . .' 

Inclination  of  cavity  walls 1 ' 

Instruments  and  instrumentation •. ^^ 

Instruments  for  packing  amalgam 130 

•SI 

Instrument  grasps 

Introduction 

1  1  Q 

Knathodynamometer 

Ligatures,  use  of 

Making  starting  points  for  packing  gold 37 

Management  of  weak  cavity  walls  in  bicuspids  and  molars 92 

1 27 

Matrix,  how  to  place 

removal  from  amalgam  fillings 130 


INomenclature. 


cavity 

instrument 

of  angles  of  cavities 13 


^^ 24 

of  enamel  margins 


of  cutting  instruments 

17 


of  internal  parts  of  cavities. 


10 


19 

111    \^av  iL  y    jji\,i^c*»**vx\j** *•  •• 

Planes  of  the  teeth 


Order  of  procedure  in  cavity  preparation 

118 

Phagodynamometer '. 

17 


108 
108 


Plugger  points,  forms  of 

Plugger,  forms  of  shanks  of   

list  of,  rcfjuired 

stepping  of  point  of  

Polishing  fillings 123.125.130 

12S 

proximate  fillings  

140 

Pulp,  anaesthetizing  the   

139 

destroying  the 

•  1  ^9 

destroying  the.  With  arsenic 

138 
exposing  the 

exposure  and  removal  of  the 

instruments  for  removing  the 

preparation  of  cavity  for  exposure  of  the 13' 

removal  of  the 


removing  the.  from  root  canals 


144 
150 


Pulp  chamber,  horns  of  the 

opening  the 

"  in  bicuspids 1^3 

"  in  bicuspids  and  molars  that  have  been  filled 148 

■'  in  distal  cavities  in  molars 143 

"  in  incisors  and  cuspids 1''3 

"  in  mesial  cavities  in  molars 1''3 


156  INDEX. 

PAGE. 

Pulp  chamber,  opening-  the,  in  occlusal  cavities  in  molars 142 

"  "  "  "    in  sound  teeth 147 

Relation  of  the  size  of  plugger  points  to  the  application  of  force 106 

Right-angle  hand-piece 36 

Root  canals,  filling 150 

"  "         finding 145 

"         rationale  of  procedures  in  filling 150 

"  "         removing  pulp  from 144 

Rubber  dam 41 

"    applying  the 42 

"  "    clamps  50 

grasps 43 

first 43 

"        second 44 

third 44 

fourth 45 

fifth 45 

ligatures  in  adjusting  the 47 

Rule  for  extension  for  prevention  in  bicuspids  and  molars 88 

Rules  for  naming  angles  of  cavities 13 

cavities 6 

walls  of  cavities 10,    11 

Separating  irregular  teeth 95 

Separating  teeth 93 

use  of  gutta-percha  in 95 

"        use  of  wood  in .■ 96 

Sharpening  instruments 32 

Strength  of  the  bite 116 

"  "      "       "    instruments  for  measuring  the 117 

"      "       "    measuring  the 117 

Use  of  the  dental  engine 34 

drills  38 

gutta-percha  in  separating  teeth 95 

ligatures 47 

water \ 38 

wood  in  separating  teeth 96 

Water,  use  of 38 

Welding  property  of  gold 99 


RK541 
Black 


B56 


filling  teeth, 

111947    9^    ^^"-^' 


^A^yT^/ 


/^^6 


COLUMBIA  UNIVERSITY  LIBRARIES  (tisl.stx) 

RK  541  B56  C.1 

The  technical  Procedures  in  tillinqte^^^^ 


2002447916 


